I am using SQL Server Management Studio 2017. I'm having a table in my local machine. Let's say its name is Email. Inside the Email table, there is a column name Language and its value can be 'en' or 'zh'. Beside this Language column, there are some more columns.
Now my colleague also has the same table but different machine and he only has the rows where Language is en. He doesn't have the rows where Language is zh yet.
How can I use this software to generate a SQL script to insert data to his table but with rows only where Language = 'zh' so that both table will be the same.
To be more clear , I need to send him the INSERT script with also contains the values of the data, so that he can use to INSERT to his database in his local machine.
Or is it any way else?
Is this what you want?
insert into colleague.dbo.email ( . . . )
select . . .
from my.dbo.email
where language = 'zh';
There are a couple of ways - the first is quick and requires no code, but you need to manually get rid of the rows you don't want yourself, the other is more flexible but you have to code it. There are also third party tools you can get to do this for you.
If you just want to do this once, you can do the following (this is from a different version of SSMS, but it should be similar)
right click on the database, select tasks, select generate scripts. Then pick the table you want, go next, then in the advanced settings find the "types of data to script" and change it to data. This should generate a script to load all the data from your table - you would need to edit it to just load the rows you want.
Another option is to write a script that basically makes the data you want yourself. You would need set it up to start with, and adjust it if you ever change the table format, but you can edit the selection script so that it only gets the data you want. I'm sure you could write a script that would create this automatically for you, but I've never needed one, so I haven't thought about it.
Something like this one
With baseRows as
(
--This bit gets the data you want
Select E.*
, ROW_NUMBER() over(ORDER BY ID) as RowNo
From dbo.Email E
Where E.Language = 'zh' -- whatever selection you need here
)
, selectRows as
(
--This bit creates the data select statments to set the data to import
Select
case when BR.RowNo = 1 then '' else 'Union All ' end
+ 'Select '
+ convert(varchar(10), BR.userID) + ' as userID, ' -- required integer example
+ case when BR.backupID is null then 'NULL' else CONVERT(varchar(10), BR.backupID) end + ' as backupID, ' -- nullable integer example
+ '''' + BR.Name + ''' as name, ' -- required nvarchar example
+ case when BR.groupname IS null then 'NULL' else '''' + BR.groupname + '''' end + ' as groupname, ' --nullable varchar example
+ CONVERT(varchar(2), BR.isActive) + ' as isActive, ' --bit example
as SQL
from baseRows BR
)
Select
--This creates the insert command row (top row) of the final query
'Insert into Email (
userID
, backupID
, name
, groupName
, IsActive
)' as SQL
UNION ALL
Select SQL from baseRows --and adds the data to the following rows
If you run this script, the output would be the script you are looking for to load the data into another machine.
RightClick on Database name(table in which Database)--->Tasks--->Generate Scripts--->Next--->select specific database objects--->select Table--->Save to file = ADVANCED--->click on Advanced--->types of data to script = "Data Only"--->Give the path(where to store theinsert commands)
Related
I am working on a sql database which will provide with data some grid. The grid will enable filtering, sorting and paging but also there is a strict requirement that users can enter free text to a text input above the grid for example
'Engine 1001 Requi' and that the result will contain only rows which in some columns contain all the pieces of the text. So one column may contain Engine, other column may contain 1001 and some other will contain Requi.
I created a technical column (let's call it myTechnicalColumn) in the table (let's call it myTable) which will be updated each time someone inserts or updates a row and it will contain all the values of all the columns combined and separated with space.
Now to use it with entity framework I decided to use a table valued function which accepts one parameter #searchQuery and it will handle it like this:
CREATE FUNCTION myFunctionName(#searchText NVARCHAR(MAX))
RETURNS #Result TABLE
( ... here come columns )
AS
BEGIN
DECLARE #searchToken TokenType
INSERT INTO #searchToken(token) SELECT value FROM STRING_SPLIT(#searchText,' ')
DECLARE #searchTextLength INT
SET #searchTextLength = (SELECT COUNT(*) FROM #searchToken)
INSERT INTO #Result
SELECT
... here come columns
FROM myTable
WHERE (SELECT COUNT(*) FROM #searchToken WHERE CHARINDEX(token, myTechnicalColumn) > 0) = #searchTextLength
RETURN;
END
Of course the solution works fine but it's kinda slow. Any hints how to improve its efficiency?
You can use an inline Table Valued Function, which should be quite a lot faster.
This would be a direct translation of your current code
CREATE FUNCTION myFunctionName(#searchText NVARCHAR(MAX))
RETURNS TABLE
AS RETURN
(
WITH searchText AS (
SELECT value token
FROM STRING_SPLIT(#searchText,' ') s(token)
)
SELECT
... here come columns
FROM myTable t
WHERE (
SELECT COUNT(*)
FROM searchText
WHERE CHARINDEX(s.token, t.myTechnicalColumn) > 0
) = (SELECT COUNT(*) FROM searchText)
);
GO
You are using a form of query called Relational Division Without Remainder and there are other ways to cut this cake:
CREATE FUNCTION myFunctionName(#searchText NVARCHAR(MAX))
RETURNS TABLE
AS RETURN
(
WITH searchText AS (
SELECT value token
FROM STRING_SPLIT(#searchText,' ') s(token)
)
SELECT
... here come columns
FROM myTable t
WHERE NOT EXISTS (
SELECT 1
FROM searchText
WHERE CHARINDEX(s.token, t.myTechnicalColumn) = 0
)
);
GO
This may be faster or slower depending on a number of factors, you need to test.
Since there is no data to test, i am not sure if the following will solve your issue:
-- Replace the last INSERT portion
INSERT INTO #Result
SELECT
... here come columns
FROM myTable T
JOIN #searchToken S ON CHARINDEX(S.token, T.myTechnicalColumn) > 0
I have table which has 100 columns. I want to write select * from table and null column values should be replaced with blank. I don't want to include 100 columns in
my select statement and write:
select
isnull(col1,''),
isnull(col2,''),
...
isnull(col100,'')
from table
Check this out :
DECLARE #TableName VARCHAR(MAX)='ASC_LOT_TBL'
DECLARE #SchemaName VARCHAR(MAX)='dbo'
DECLARE #ColumnList VARCHAR(MAX)
SELECT #ColumnList= ISNULL(#ColumnList+',','')+
CASE WHEN DATA_TYPE LIKE '%char' THEN 'ISNULL('+COLUMN_NAME+','''') AS '+COLUMN_NAME
WHEN DATA_TYPE = 'int' THEN 'ISNULL('+COLUMN_NAME+',''0'') AS '+COLUMN_NAME
ELSE COLUMN_NAME END
FROM INFORMATION_SCHEMA.COLUMNS
where TABLE_NAME=#TableName
AND TABLE_SCHEMA=#SchemaName
ORDER BY ORDINAL_POSITION
SELECT 'SELECT '+#ColumnList+' FROM ' +#SchemaName+'.'+#TableName
Well, you can go over all the suggestion above on SQL/script level, or change your design on your table to not allow NULL and with a default value to '' (In MSSQL, it will be ('')).
This way, when a new entry is inserted, that column will store the data/value '', not NULL.
And in this case, you can select * from table with "blank" in return instead of NULL.
You need to choose from script or table design, one way or another.
X/Y problem apart, to answer your specific question :
To write the query you can use a regular expression search & replace in your editor to avoid editing each line a hundred time.
Just select all the concerned lines with the columns names after the SELECT,
col1,
col2,
col3,
...
Open search and replace (Ctrl + H) for (\S+), and replace by ISNULL($1, ''),, with the regular expression mode activated in your favorite editor, and apply the replacement to the selection only.
Illustration in SSMS :
It works for instance in Visual Studio, in SQL Server Management Studio, in Notepad++, etc...
(provided there is no space in your column names, otherwise please leave a comment to specify how your column names are, and we can work out a quick solution)
The last line need to be edited manually, but you saved 99 editions anyway ;).
You should also be able to create a view, and then do SELECT on your view, this would reduce the need to write this only once (but not tested, and not sure if there could be performance issue in your usecase)
Doing this seemingly trivial task should be simple and obvious using PIVOT - but isn't.
What is the cleanest way to do the conversion, not necessarily using pivot, when limited to ONLY using "pure" SQL (see other factors, below)?
It shouldn't affect the answer, but note that a Python 3.X front end is being used to run SQL queries on a MS SQL Server 2012 backend.
Background :
I need to create CSV files by calling SQL code from Python 3.x. The CSV header line is created from the field (column) names of the SQL table that holds the results of the query.
The following SQL code extracts the field names and returns them as N rows of 1 column - but I need them as 1 row of N columns. (In the example below, the final result must be "A", "B", "C" .)
CREATE TABLE #MyTable -- ideally the real code uses "DECLARE #MyTable TABLE"
(
A varchar( 32 ),
B varchar( 32 ),
C varchar( 32 )
) ;
CREATE TABLE #MetaData -- ideally the real code uses "DECLARE #MetaData TABLE"
(
NameOfField varchar( 32 ) not NULL
) ;
INSERT INTO #MetaData
SELECT name
FROM tempdb.sys.columns as X
WHERE ( object_id = Object_id( 'tempdb..#MyTable' ) )
ORDER BY column_id ; -- generally redundant, ensures correct order if results returned in random order
/*
OK so far, the field names are returned as 3 rows of 1 column (entitled "NameOfField").
Pivoting them into 1 row of 3 columns should be something simple like:
*/
SELECT NameOfField
FROM #MetaData AS Source
PIVOT
(
COUNT( [ NameOfField ] ) FOR [ NameOfField ]
IN ( #MetaData ) -- I've tried "IN (SELECT NameOfField FROM #Metadata)"
) AS Destination ;
This error gets raised twice, once for the COUNT and once for the "FOR" clause of the PIVOT statement:
Msg 207, Level 16, State 1, Line 32
Invalid column name ' NameOfField'.
How do I use the contents of #Metadata to get PIVOT to work? Or is there another simple way?
Other background factors to be aware of:
OBDC (Python's pyodbc package) is being used to pass the SQL queries from - and return the results (a cursor) to - a Python 3.x front end. Consequently there is no opportunity to use any type of manual intervention before the result set is returned to Python.
The above SQL code is intended to become standard boilerplate for every query passed to SQL. The code must dynamically "adapt" itself to the structure of #MyTable (e.g. if field B is removed while D and E are added after C, the end result must be "A", "C","D", "E"). This means that the field names of a table must never appear inside PIVOT's IN clause (the #MetaData table is intended to supply those values).
"Standard" SQL must be used. ALL vendor specific (e.g. Microsoft) extensions/utilities (e.g. "bcp", sqlcmd) must be avoided unless there is a very compelling reason to use them (because "it's there" doesn't count).
For known reasons the select clause (into #Metadata) doesn't work for temporary variables (#MyTable). Is there an equivalent Select that works for temporary variables(i.e. #MetaData)?
UPDATE: This problem is subtly different from that in SQL Server dynamic PIVOT query?. In my case I have to preserve the order of the fields, something not required by that question.
WHY I NEED TO DO THIS:
The python code is a GUI for non-technical people. They use the GUI to pick & chose which (or even all) SQL reports to run from a HUGE number of reports.
Apps like Excel are being used to view these files: to keep our users happy each CSV file must have a header line. The header line will consist of the field names from the SQL table that holds the results of the query.
These scripts can change at any time (e.g. add/delete a column) without any advance notice. To meet our users needs the header line must automatically "adjust itself" to make the corresponding changes. The SQL code below accomplishes this.
The header line gets merged (using UNION) with the query results to form the result set (a cursor) that gets passed back to Python. Python then processes the returned data and creates the CSV file (including the header line) that gets used by our customers.
In a nutshell: We have many sites, many users, many queries. By having SQL "dynmically create" the header line we remove the headache of having to manually manage/coordinate/rollout the SQL changes to all affected parties.
I am unsure what "pure" sql is. Are you refering to ANSI-92 SQL?
Anyhow, if you can use SQL variables, try this:
DECLARE #STRING VARCHAR(MAX)
SELECT #STRING = COALESCE(#STRING + ', ' + '"' + NameOfField + '"', '"' + NameOfField + '"')
FROM #MetaData
SELECT #STRING
/*
Results:
"A", "B", "C"
*/
To #Tab Alleman, thanks. I was able to modify the answer to SQL Server dynamic PIVOT query?
to do the swap (see below) in a way that meets all my needs.
NOTE: For some reason the "DISTINCT" keyword places the fields in alphabetical order - something I don't want.
Commenting that word out (as done below) preserves the order of the fields. I'm a bit uneasy about doing this but in this case it should be safe because the values being selected into #MetaData are guaranteed to be unique.
The difference can be easily seen by swapping fields A & B in #MyTable and uncommenting the "DISTINCT" keyword
--drop table #MyTable
--drop table #MetaData
Create TABLE #MyTable
(
A varchar( 10 ),
B varchar( 10 ),
C varchar( 10 )
)
;
CREATE TABLE #MetaData
(
NameOfField varchar( 100 ) not NULL,
Position int
)
;
INSERT INTO #MetaData
SELECT name, column_id
FROM tempdb.sys.columns as X
WHERE ( object_id = Object_id( 'tempdb..#MyTable' ) )
--ORDER BY column_id -- normally redundant, guards against results being returned in random order
;
select * from #MetaData
DECLARE #cols AS NVARCHAR(MAX),
#query AS NVARCHAR(MAX);
SET #cols = STUFF( (SELECT
-- DISTINCT
',' + QUOTENAME( c.NameOfField )
FROM #MetaData AS c
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
--print( #cols )
set #query = 'SELECT ' + #cols + ' from
(
select NameOfField
from #MetaData
) AS x
pivot
(
MAX( NameOfField )
for NameOfField in ( '+ #cols + ' )
) AS p
'
--print( #query )
execute( #query )
drop table #MyTable
drop table #MetaData
sql2005
This is my simplified example:
(in reality there are 40+ tables in here, I only showed 2)
I got a table called tb_modules, with 3 columns (id, description, tablename as varchar):
1, UserType, tb_usertype
2, Religion, tb_religion
(Last column is actually the name of a different table)
I got an other table that looks like this:
tb_value (columns:id, tb_modules_ID, usertype_OR_religion_ID)
values:
1111, 1, 45
1112, 1, 55
1113, 2, 123
1114, 2, 234
so, I mean 45, 55, 123, 234 are usertype OR religion ID's
(45, 55 usertype, 123, 234 religion ID`s)
Don't judge, I didn't design the database
Question
How can I make a select, showing * from tb_value, plus one column
That one column would be TITLE from the tb_usertype or RELIGIONNAME from the tb_religion table
I would like to make a general thing.
Was thinking initially about maybe a SQL function that returns a string, but I think I would need dynamic SQL, which is not ok in a function.
Anyone a better idea ?
At the beginning we have this -- which is quite messy.
To clean-up a bit I add two views and a synonym:
create view v_Value as
select
ID as ValueID
, tb_modules_ID as ModuleID
, usertype_OR_religion_ID as RemoteID
from tb_value ;
go
create view v_Religion as
select
ID
, ReligionName as Title
from tb_religion ;
go
create synonym v_UserType for tb_UserType ;
go
And now the model looks like
It is easier now to write the query
;
with
q_mod as (
select
m.ID as ModuleID
, coalesce(x1.ID , x2.ID) as RemoteID
, coalesce(x1.Title , x2.Title) as Title
, m.Description as ModuleType
from tb_Modules as m
left join v_UserType as x1 on m.TableName = 'tb_UserType'
left join v_Religion as x2 on m.TableName = 'tb_Religion'
)
select
a.ModuleID
, v.ValueID
, a.RemoteID
, a.ModuleType
, a.Title
from q_mod as a
join v_Value as v on (v.ModuleID = a.ModuleID and v.RemoteID = a.RemoteID) ;
There is an obvious pattern in this query, so it can be created as dynamic sql if you have to add another module-type table. When adding another table, use ID and Title to avoid having to use a view.
EDIT
To build dynamic sql (or query on application level)
Modify lines 6 and 7, the x-index is tb_modules.id
coalesce(x1. , x2. , x3. ..)
Add lines to the left join (below line 11)
left join v_SomeName as x3 on m.TableName = 'tb_SomeName'
The SomeName is tb_modules.description and x-index is matching tb_modules.id
EDIT 2
The simplest would probably be to package the above query into a view and then each time the schema changes dynamically crate and run ALTER VIEW. This way the query would not change from the point of the application.
Since we're all agreed the design is flaky, I'll skip any comments on that. The pattern of the query is this:
-- Query 1
select tb_value.*,tb_religion.religion_name as ANY_DESCRIPTION
from tb_value
JOIN tb_religion on tb_value.ANY_KIND_OF_ID = tb_religion.id
WHERE tb_value.module_id = 2
-- combine it with...
UNION ALL
-- ...Query 2
select tb_value.*,tb_religion.title as ANY_DESCRIPTION
from tb_value
JOIN tb_userType on tb_value.ANY_KIND_OF_ID = tb_userType.id
WHERE tb_value.module_id = 1
-- combine it with...
UNION ALL
-- ...Query 3
select lather, rinse, repeat for 40 tables!
You can actually define a view that hardcodes all 40 cases, and then put filters onto queries for the particular modules you want.
To do this dynamically you need to be able to create a sql statement that looks like this
select tb_value.*, tb_usertype.title as Descr
from tb_value
inner join tb_usertype
on tb_value.extid = tb_usertype.id
where tb_value.tb_module_id = 1
union all
select tb_value.*, tb_religion.religionname as Descr
from tb_value
inner join tb_religion
on tb_value.extid = tb_religion.id
where tb_value.tb_module_id = 2
-- union 40 other tables
Currently you can not do that because you do not have any information in the db telling you which column to use from tb_religion and tb_usertype etc. You can add that as a new field in tb_module.
If you have fieldname to use in tb_module you can build a view that does what you want.
And you could add a trigger to table tb_modules that alters the view whenever tb_modules is modified. That way you do not need to use dynamic sql from the client when doing queries. The only thing you need to worry about is that the table needs to be created in the db before you add a new row to tb_modules
Edit 1
Of course the code in the trigger needs to dynamically build the alter view statement.
Edit 2 You also need to have a field with information about what column in tb_usertype and tb_religion etc. to join against tb_value.extid (usertype_OR_religion_ID). Or you can assume that the field will always be called id
Edit 3 Here is how you could build the trigger on tb_module that alters the view v_values. I have added fieldname as a column in tb_modules and I assume that the id field in the related tables is called id.
create trigger tb_modules_change on tb_modules after insert, delete, update
as
declare #sql nvarchar(max)
declare #moduleid int
declare #tablename varchar(50)
declare #fieldname varchar(50)
set #sql = 'alter view v_value as '
declare mcur cursor for
select id, tablename, fieldname
from tb_modules
open mcur
fetch next from mcur into #moduleid, #tablename, #fieldname
while ##FETCH_STATUS = 0
begin
set #sql = #sql + 'select tb_value.*, '+#tablename+'.'+#fieldname+' '+
'from tb_value '+
'inner join '+#tablename+' '+
'on tb_value.extid = '+#tablename+'.id '+
'where tb_value.tb_module_id = '+cast(#moduleid as varchar(10))
fetch next from mcur into #moduleid, #tablename, #fieldname
if ##FETCH_STATUS = 0
begin
set #sql = #sql + ' union all '
end
end
close mcur
deallocate mcur
exec sp_executesql #sql
Hm..there are probably better solutions available but here's my five cents:
SELECT
id,tb_modules_ID,usertype_OR_religion_ID,
COALESCE(
(SELECT TITLE FROM tb_usertype WHERE Id = usertype_OR_religion_ID),
(SELECT RELIGIONNAME FROM tb_religion WHERE Id = usertype_OR_religion_ID),
'N/A'
) AS SourceTable
FROM tb_valuehere
Note that I don't have the possibility to check the statement right now so I'm reserving myself for any syntax errors...
First, using your current design the only reasonable solution is dynamic SQL. You should write a module in your middle-tier that queries for the appropriate table names and builds the queries on the fly. Trying to accomplish that in T-SQL will be a nightmare. T-SQL was not designed for string construction.
The right solution is to build a new database designed properly, migrate the data and scrap the existing design. The problems you will encounter with your current design will simply grow. It will be harder for new developers to learn the new system. It will be prone to errors. There will be no data integrity (e.g. forcing the attribute "Start Date" to be parsable as a date). Custom queries will be a chore to write and so on. Eventually, you will hit the day when the types of information desired from the system are simply too difficult to extract given the current design.
First take the undesigner out the back and put them out of their misery. They are hurting people.
Due to their incompetence, every time you add a row to Module, you have to modify every query that uses it. Good for www.dailywtf.com.
You do not have Referential Integrity either, because you cannot define an FK on the this_or_that column. Your data is exposed, probably to "code" written by the same undesigner. No doubt you are aware that this is where the deadlocks are created.
That it is a "judgement", that is so that you understand the gravity of the undesign, and you can justify replacing it, to your managers.
SQL was designed for Relational Databases, that means Normalised. It is not good for mangled files. Sure, some queries may be better than others (just look at the answers), but there is no way to get around the undesign, any SQL query will be hamstrung, and need change whenever a Module row is added.
"Dynamic" is reserved for Databases, not possible for flat flies.
Two answers. One to stop the continuing idiocy of changing the existing queries every time a Module row is added (you're welcome); the second to answer your question.
Safe Future Queries
CREATE VIEW UserReligion_vw AS
SELECT [XxxxId] = id, -- replace Xxxx
[ReligionId] = usertype_OR_religion_ID
FROM tb_value
WHERE tb_modules_ID = 1
CREATE VIEW UserReligion_vw AS
SELECT [XxxxId] = id,
[ReligionId] = usertype_OR_religion_ID
FROM tb_value
WHERE tb_modules_ID = 2
From now on, make sure the all queries currently using the undesign, are modified to use the correct View instead. Do not use the Views for Update/Delete/Insert.
Answer
Ok, now for the main question. I can think of other approaches, but this one is the best. You have stated, you want the third column to also be an unnormalised piece of chicken excreta and the supply Title for [EITHER_Religion_OR_UserType_OR_This_OR_That]. Right, so you are teaching the user to be confused as well; when the no of modules grow, they will have great fun figuring out what the column contains. Yes a problem does always compound itself.
SELECT [XxxxId] = id,
[Whatever] = CASE tb_modules_ID
WHEN 1 THEN ( SELECT name -- title, whatever
FROM tb_religion
WHERE id = V.usertype_OR_religion_ID
)
WHEN 2 THEN ( SELECT name -- title, whatever
FROM tb_usertype
WHERE id = V.usertype_OR_religion_ID
)
ELSE "(UnknownModule)" -- do not remove the brackets
END
FROM tb_value V
WHERE conditions... -- you need something here
This is called a Correlated Scalar Subquery.
It works on any version of Sybase since 4.9.2 with no limitations. And SQL 2005 (last time I looked, anyway, Aug 2009). But on MS you will get a StackTrace if the volume of tb_value is large, so make sure the WHERE clause has some conditions on it.
But MS have broken the server with their "new" 2008 codeline, so it does not work in all circumstances (the worse your mangled files, the less likely it will work; the better your database design, the more likely it will work). That is why some MS people pray every day for the next Service pack, and others never attend church.
I guess you want something like this:
Adding tables and one row per table into tb_modules is straight forward.
SET NOCOUNT ON
if OBJECT_ID('tb_modules') > 0 drop table tb_modules;
if OBJECT_ID('tb_value') > 0 drop table tb_value;
if OBJECT_ID('tb_usertype') > 0 drop table tb_usertype;
if OBJECT_ID('tb_religion') > 0 drop table tb_religion;
go
create table dbo.tb_modules (
id int,
description varchar(20),
tablename varchar(255)
);
insert into tb_modules values ( 1, 'UserType', 'tb_usertype');
insert into tb_modules values ( 2, 'Religion', 'tb_religion');
create table dbo.tb_value(
id int,
tb_modules_ID int,
usertype_OR_religion_ID int
);
insert into tb_value values ( 1111, 1, 45);
insert into tb_value values ( 1112, 1, 55);
insert into tb_value values ( 1113, 2, 123);
insert into tb_value values ( 1114, 2, 234);
create table dbo.tb_usertype(
id int,
UserType varchar(30)
);
insert into tb_usertype values ( 45, 'User_type_45');
insert into tb_usertype values ( 55, 'User_type_55');
create table dbo.tb_religion(
id int,
Religion varchar(30)
);
insert into tb_religion values ( 123, 'Religion_123');
insert into tb_religion values ( 234, 'Religion_234');
-- start of query
declare #sql varchar(max) = null
Select #sql = case when #sql is null then ' ' else #sql + char(10) + 'union all ' end
+ 'Select ' + str(id) + ' type, id, ' + description + ' description from ' + tablename from tb_modules
set #sql = 'select v.id, tb_modules_ID , usertype_OR_religion_ID , t.description
from tb_value v
join ( ' + #sql + ') as t
on v.tb_modules_ID = t.type and v.usertype_OR_religion_ID = t.id
'
Print #sql
exec( #sql)
I think it's intended to be used with dynamic sql.
Maybe break out each tb_value.tb_modules_ID row into its own temp table, named with the tb_modules.tablename.
Then have an sp iterate through the temp tables matching your naming convention (by prefix or suffix) building the sql and doing your join.
i have three checkboxs in my application. If the user ticks a combination of the boxes i want to return matches for the boxes ticked and in the case where a box is not checked i just want to return everything . Can i do this with single SQL command?
I recommend doing the following in the WHERE clause;
...
AND (#OnlyNotApproved = 0 OR ApprovedDate IS NULL)
It is not one SQL command, but works very well for me. Basically the first part checks if the switch is set (checkbox selected). The second is the filter given the checkbox is selected. Here you can do whatever you would normally do.
You can build a SQL statement with a dynamic where clause:
string query = "SELECT * FROM TheTable WHERE 1=1 ";
if (checkBlackOnly.Checked)
query += "AND Color = 'Black' ";
if (checkWhiteOnly.Checked)
query += "AND Color = 'White' ";
Or you can create a stored procedure with variables to do this:
CREATE PROCEDURE dbo.GetList
#CheckBlackOnly bit
, #CheckWhiteOnly bit
AS
SELECT *
FROM TheTable
WHERE
(#CheckBlackOnly = 0 or (#CheckBlackOnly = 1 AND Color = 'Black'))
AND (#CheckWhiteOnly = 0 or (#CheckWhiteOnly = 1 AND Color = 'White'))
....
sure. example below assumes SQL Server but you get the gist.
You could do it pretty easily using some Dynamic SQL
Lets say you were passing your checkboxes to a sproc as bit values.
DECLARE bit #cb1
DECLARE bit #cb2
DECLARE bit #cb3
DECLARE nvarchar(max) #whereClause
IF(#cb1 = 1)
SET #whereClause = #whereClause + ' AND col1 = ' + #cb1
IF(#cb2 = 1)
SET #whereClause = #whereClause + ' AND col2 = ' + #cb2
IF(#cb3 = 1)
SET #whereClause = #whereClause + ' AND col3 = ' + #cb3
DECLARE nvarchar(max) #sql
SET #sql = 'SELECT * FROM Table WHERE 1 = 1' + #whereClause
exec (#sql)
Sure you can.
If you compose your SQL SELECT statement in the code, then you just have to generate:
in case nothing or all is selected (check it using your language), you just issue non-filter version:
SELECT ... FROM ...
in case some checkboxes are checked, you create add a WHERE clause to it:
SELECT ... FROM ... WHERE MyTypeID IN (3, 5, 7)
This is single SQL command, but it is different depending on the selection, of course.
Now, if you would like to use one stored procedure to do the job, then the implementation would depend on the database engine since what you need is to be able to pass multiple parameters. I would discourage using a procedure with just plain 3 parameters, because when you add another check-box, you will have to change the SQL procedure as well.
SELECT *
FROM table
WHERE value IN
(
SELECT option
FROM checked_options
UNION ALL
SELECT option
FROM all_options
WHERE NOT EXISTS (
SELECT 1
FROM checked_options
)
)
The inner subquery will return either the list of the checked options, or all possible options if the list is empty.
For MySQL, it will be better to use this:
SELECT *
FROM t_data
WHERE EXISTS (
SELECT 1
FROM t_checked
WHERE session = 2
)
AND opt IN
(
SELECT opt
FROM t_checked
WHERE session = 2
)
UNION ALL
SELECT *
FROM t_data
WHERE NOT EXISTS (
SELECT 1
FROM t_checked
WHERE session = 2
)
MySQL will notice IMPOSSIBLE WHERE on either of the SELECT's, and will execute only the appropriate one.
See this entry in my blog for performance detail:
Selecting options
If you pass a null into the appropriate values, then it will compare that specific column against itself. If you pass a value, it will compare the column against the value
CREATE PROCEDURE MyCommand
(
#Check1 BIT = NULL,
#Check2 BIT = NULL,
#Check3 BIT = NULL
)
AS
SELECT *
FROM Table
WHERE Column1 = ISNULL(#Check1, Column1)
AND Column2 = ISNULL(#Check2, Column2)
AND Column3 = ISNULL(#Check3, Column3)
The question did not specify a DB product or programming language. However it can be done with ANSI SQL in a cross-product manner.
Assuming a programming language that uses $var$ for variable insertion on strings.
On the server you get all selected values in a list, so if the first two boxes are selected you would have a GET/POST variable like
http://url?colors=black,white
so you build a query like this (pseudocode)
colors = POST['colors'];
colors_list = replace(colors, ',', "','"); // separate colors with single-quotes
sql = "WHERE ('$colors$' == '') OR (color IN ('$colors_list$'));";
and your DB will see:
WHERE ('black,white' == '') OR (color IN ('black','white')); -- some selections
WHERE ('' == '') OR (color IN ('')); -- nothing selected (matches all rows)
Which is a valid SQL query. The first condition matches any row when nothing is selected, otherwise the right side of the OR statement will match any row that is one of the colors. This query scales to an unlimited number of options without modification. The brackets around each clause are optional as well but I use them for clarity.
Naturally you will need to protect the string from SQL injection using parameters or escaping as you see fit. Otherwise a malicious value for colors will allow your DB to be attacked.