I need some help with using a cursor and variable to populate a query. I am using SQL Server 2008 R2.
What I am trying to do is populate a temp table with inserts, run through the one column of data to generate a variable that will then populate a query that will check the number of rows in a table. Here is what I have so far:
IF OBJECT_ID('tempdb..#part_tables') IS NOT NULL DROP TABLE #part_tables
create table #Part_tables
(table_Name nvarchar(100))
Insert INTO #Part_Tables (table_name)
SELECT [InstancesTable] FROM [BAMPrimaryImport].[dbo].[bam_Metadata_Partitions]
WHERE [ArchivingInProgress]=0 and ArchivedTime IS NULL
and creationtime < dateadd(DD,-21,getdate())
GO
Insert INTO #Part_Tables (table_name)
SELECT [RelationshipsTable] FROM [BAMPrimaryImport].[dbo].[bam_Metadata_Partitions]
WHERE [ArchivingInProgress]=0 and ArchivedTime IS NULL
and creationtime < dateadd(DD,-21,getdate())
GO
DECLARE #count_query VARCHAR(MAX)
DECLARE #Value NVARCHAR(100)
SET #Value ='Select Table_Name from #Part_Tables'
SET #count_query ='
select count (*) from #Value with (NOLOCK)'
WHILE 1 = 1
BEGIN
EXEC(#count_query + ' option(maxdop 5) ')
IF ##rowcount < 1 BREAK;
END
If this will work, great! If you have a different / better way to do it, I would appreciate any guidance that someone could offer.
Here is a much simpler way to get the row counts from those tables. No need for cursors or while loops. And be careful with that NOLOCK hint...it can do a lot more than just dirty reads. http://blogs.sqlsentry.com/aaronbertrand/bad-habits-nolock-everywhere/
declare #SQL nvarchar(max) = ''
select #SQL = #SQL + 'select count(*) from ' + QUOTENAME(InstancesTable) + ' UNION ALL '
FROM [BAMPrimaryImport].[dbo].[bam_Metadata_Partitions]
WHERE [ArchivingInProgress] = 0
and ArchivedTime IS NULL
and creationtime < dateadd(Day, -21, getdate())
set #SQL = LEFT(#SQL, len(#SQL) - 10)
select #SQL --uncomment exec statement below when satisfied this is correct
--exec sp_executesql #SQL
Related
I have tried a bunch of different ways like using cursors and dynamic SQL, but is there a fast way to verify that all columns in a given table can convert from varchar to float (without altering the table)?
I want to get a print out of which columns fail and which columns pass.
I am trying this method now but it is slow and cannot get the list of columns that pass or error out.
drop table users;
select *
into users_1
from users
declare #cols table (i int identity, colname varchar(100))
insert into #cols
select column_name
from information_schema.COLUMNS
where TABLE_NAME = 'users'
and COLUMN_NAME not in ('ID')
declare #i int, #maxi int
select #i = 1, #maxi = MAX(i) from #cols
declare #sql nvarchar(max)
while(#i <= #maxi)
begin
select #sql = 'alter table users_1 alter column ' + colname + ' float NULL'
from #cols
where i = #i
exec sp_executesql #sql
select #i = #i + 1
end
I found this code on one of the SQL tutorials sites.
Why all the drop/create/alter nonsense? If you just want to know if a column could be altered, why leave your table in a wacky state, where the columns that can be altered are altered, and the ones that can't just raise errors?
Here's one way to accomplish this with dynamic SQL (and with some protections):
DECLARE #tablename nvarchar(513) = N'dbo.YourTableName';
IF OBJECT_ID(#tablename) IS NOT NULL
BEGIN
DECLARE #sql nvarchar(max) = N'SELECT ',
#tmpl nvarchar(max) = N'[Can $colP$ be converted?]
= CASE WHEN EXISTS
(
SELECT 1 FROM ' + #tablename + N'
WHERE TRY_CONVERT(float, COALESCE($colQ$,N''0'')) IS NULL
)
THEN ''No, $colP$ cannot be coverted''
ELSE ''Yes, $colP$ CAN be converted'' END';
SELECT #sql += STRING_AGG(
REPLACE(REPLACE(#tmpl, N'$colQ$',
QUOTENAME(name)), N'$colP$', name), N',')
FROM sys.columns
WHERE object_id = OBJECT_ID(#tablename)
AND name <> N'ID';
EXEC sys.sp_executesql #sql;
END
Working db<>fiddle
This is never going to be "fast" - there is no great shortcut to having to read and validate every value in the table.
Suppose I have the following structure to a set of tables in my SQL Server (2012) DB:
StartDate: Col1: Col2: .... Coln:
And, the way the DBA set up the database (have no control over that - I only have query access), all the tables with this structure that I'd want to query have, say, names beginning with MyTbl....
So, I would like to create a query that queries ALL these tables at once to get data for a specific StartDate and I've done it using the following SQL:
declare #t table(tablename varchar(50))
declare #sql varchar(max)
set #sql = ''
insert into #t
SELECT t.name AS table_name FROM sys.tables AS t
WHERE t.name LIKE 'MyTbl%'
select #sql = #sql + 'Select ''' + tablename + ''' as Table_Name, t.* From ' + tablename +
' t where StartDate = ''2015-01-01'' +
' union ' from #t
Select #sql = substring(#sql, 1, len(#sql) - 6)
exec(#sql)
In other words:
Find all tables in my DB with names beginning with MyTbl
Query each table for any data with StartDate = '2015-01-01`
Union all those queries together to get one big dataset result
The SQL works perfectly, but I'm getting quite stuck in creating a stored procedure from this query that can take in a parameter for StartDate and I don't know enough about stored procedures to do this correctly.
How could I convert this into a stored procedure that takes a date in for StartDate (to replace the ''2015-01-01'' in the query)?
Any help / guidance would be GREATLY appreciated!!!
THANKS!!!
I noticed you were not looping through each table .. here is something I had put together
CREATE PROCEDURE get_tabledata (#date DATE)
AS
BEGIN
DECLARE #t TABLE (
id INT IDENTITY(1, 1)
,tablename VARCHAR(50)
)
DECLARE #id INT
DECLARE #tablename VARCHAR(max)
DECLARE #sql VARCHAR(max)
SET #sql = ''
INSERT INTO #t
SELECT t.NAME AS table_name
FROM sys.tables AS t
WHERE t.NAME LIKE 'MyTbl%'
SET #id = ##ROWCOUNT
IF (#id > 0)
BEGIN
WHILE (#id > 0)
BEGIN
SET #tablename = (
SELECT tablename
FROM #t
WHERE id = #id
)
SELECT #sql = #sql + 'Select ' + #tablename + ''' as Table_Name, t.* From ' + #tablename + ' t where StartDate = ' + '' + convert(VARCHAR, #date) + ''
SET #sql = #sql + ' union'
Set #id = #id -1;
END
SELECT #sql = substring(#sql, 1, len(#sql) - 6)
END
EXEC (#sql)
END
While it can be a little dense if you're not used to the styling Microsoft uses on these pages, the best place to start would be the Create Procedure documentation on MSDN
https://msdn.microsoft.com/en-us/library/ms187926.aspx
That said, creating a stored procedure is pretty straight forward. Here's a really simple procedure that takes a #startDate parameter and then just returns it back. This is just to illustrate how and where you define your parameters
create procedure dbo.MyProcedure
-- put your input parameters here
#StartDate date
as
--put the body of your procedure (i.e. everything you've written in your OP) here
select #StartDate
go
YOu'll notice however that if you run this twice in a row, you get an error, because it tries to build the same procedure again. Another thing which can come in handy is adding some code before your procedure which will basically check to see if it already exists, and if it does, alter the procedure rather than just blindly re-create it.
This is a snippet from a template I use quite often which handles all of that logic for you. The simplest way to use this is press CTRL-SHIFT-M, which brings up a dialogue to replace all those tags with values you provide.
use [<Database Name, sysname,>]
go
if not exists (select 1
from sys.procedures with(nolock)
where name = '<Procedure Name, sysname,>'
and [schema_id] = schema_id('<Schema, sysname,dbo>')
and type = 'P'
)
exec ('create procedure [<Schema, sysname,dbo>].[<Procedure Name, sysname,>]
as
select ''Procedure not defined.'' as ErrorDescription
return')
--Executed as dynamic SQL since SQL Server Management Studio considures the straight SQL code a syntax error for some reason on the create procedure statement
GO
alter procedure [<Schema, sysname,dbo>].[<Procedure Name, sysname,>]
<Parm 1 Name, sysname,include [#]> <Parm 1 Datatype, sysname,><Parm 1 Default, sql_variant,include [=] if used>,
<Parm 2 Name, sysname,include [#]> <Parm 2 Datatype, sysname,><Parm 2 Default, sql_variant,include [=] if used>
as
/*******************************************************************************************************
********************************************************************************************************/
---------------------------------------------
-- declare variables
---------------------------------------------
---------------------------------------------
-- create temp tables
---------------------------------------------
---------------------------------------------
-- set session variables
---------------------------------------------
set nocount on
---------------------------------------------
-- body of stored procedure
---------------------------------------------
return
I have fairly new to using SQL, currently I have a table that has a column that contains the names of all the tables I want to use for one query, so what I want to do is to loop through that column and go to every single one of these tables and then search one of their columns for a value (there could be multiple values), so whenever a table contains the value, I will list the name of the table. Could someone give me a hint of how this is done? Is cursor needed for this?
I don't have enough reputation to comment but is the table with the column that contain the table names all in one column, meaning that all the table names are comma separated or marked with some sort of separator? This would cause the query to be a little more complicated as you would have to take care of that before you start looping through your table.
However, this would require a cursor, as well as some dynamic sql.
I will give a basic example of how you can go about this.
declare #value varchar(50)
declare #tableName varchar(50)
declare #sqlstring nvarchar(100)
set #value = 'whateveryouwant'
declare #getTableName = cursor for
select tableName from TablewithTableNames
OPEN #getTableName
fetch NEXT
from #getTableName into #tableName
while ##FETCH_STATUS = 0
BEGIN
set #sqlstring = 'Select Count(*) from ' + #tableName + 'where ColumnNameYouwant = ' + #value
exec #sqlstring
If ##ROWcount > 0
insert into #temptable values (#tableName)
fetch next
from #getTableName into #tableName
END
select * from #temptable
drop table #temptable
close #getTableName
deallocate #getTableName
I'm currently not able to test this out as for time constraint reasons, but this is how I would go about doing this.
You could try something like this:
--Generate dynamic SQL
DECLARE #TablesToSearch TABLE (
TableName VARCHAR(50));
INSERT INTO #TablesToSearch VALUES ('invoiceTbl');
DECLARE #SQL TABLE (
RowNum INT,
SQLText VARCHAR(500));
INSERT INTO
#SQL
SELECT
ROW_NUMBER() OVER (ORDER BY ts.TableName) AS RowNum,
'SELECT * FROM ' + ts.TableName + ' WHERE ' + c.name + ' = 1;'
FROM
#TablesToSearch ts
INNER JOIN sys.tables t ON t.name = ts.TableName
INNER JOIN sys.columns c ON c.object_id = t.object_id;
--Now run the queries
DECLARE #Count INT;
SELECT #Count = COUNT(*) FROM #SQL;
WHILE #Count > 0
BEGIN
DECLARE #RowNum INT;
DECLARE #SQLText VARCHAR(500);
SELECT TOP 1 #RowNum = RowNum, #SQLText = SQLText FROM #SQL;
EXEC (#SQLText);
DELETE FROM #SQL WHERE RowNum = #RowNum;
SELECT #Count = COUNT(*) FROM #SQL;
END;
You would need to change the "1" I am using as an example to the value you are looking for and probably add a CONVERT/ CAST to make sure the column is the right data type?
You actually said that you wanted the name of the table, so you would need to change the SQL to:
'SELECT ''' + ts.TableName + ''' FROM ' + ts.TableName + ' WHERE ' + c.name + ' = 1;'
Another thought, it would probably be best to insert the results from this into a temporary table so you can dump out the results in one go at the end?
In a stored procedure I pass a table name as the input variable.
I want to return the number of rows of this table with that stored procedure.
I tried something like this but it did not work:
declare #maxRowCount bigint
exec('set '+ #maxRowCount + ' =(select COUNT(1) from ' + #tableName + ')')
This is SQL Server 2008.
You can try this
CREATE PROCEDURE dbo.sp_selectcount
#tablename NVARCHAR(200)
AS
DECLARE #cmd NVARCHAR (255)
SET #cmd = 'SELECT count(*) from ' + #tablename
EXEC sp_executesql #cmd
The following example should give you something to work with.
-- fully qualify your table name (this is probably an input value in your sproc?)
-- please note that I use system view master.sys.tables as an example table here
DECLARE #tablename NVARCHAR(MAX) = N'[master].[sys].[tables]';
-- build the sql statement that you will execute
DECLARE #sql NVARCHAR(MAX) = N'SELECT COUNT(*) FROM ' + #tablename;
-- create a variable to hold the number of rows later on
DECLARE #nrofrows BIGINT;
-- create a temp table to store the result of executing the sql statement
CREATE TABLE #temp (NrOfRows BIGINT);
-- insert the result of the execution of the sql statement into the temp table
INSERT INTO #temp
EXECUTE(#sql);
-- extract the number of rows from the temp table
SET #nrofrows = (SELECT NrOfRows FROM #temp);
-- check the result so you can test!
PRINT #nrofrows;
If you want good background information on dynamic SQL, check out Erland Sommarskogs article The Curse and Blessings of Dynamic SQL.
You should remove the quotes around #maxRowCount.
Try this:
declare #maxRowCount bigint
exec('set #maxRowCount =(select COUNT(*) from ' + #tableName + ')')
OR
exec('SELECT #maxRowCount = COUNT(*) from ' + #tableName)
Analysis:
With the query you tried, it will execute:
set blablabla = (select count(1) from MyTable)
By removing the quotes:
set #maxRowCount = (select count(*) from MyTable)
You can try this instead.
declare #maxRowCount bigint(5)
exec('SELECT COUNT(*) INTO #maxRowCount FROM ' + #tableName)
I have a stored procedure which takes 'table name' as parameter. I want to store my 'exec' results to a variable and display using that variable.
Here is my T-SQL stored procedure..
create procedure DisplayTable( #tab varchar(30))
as
begin
Declare #Query VARCHAR(30)
set #Query='select * from ' +#tab
EXEC (#Query)
END
I want to do something like this..
SET #QueryResult = EXEC (#Query)
select #QueryResult
How do i achieve this.. Please help.. I am a beginner..
You can use XML for that. Just add e.g. "FOR XML AUTO" at the end of your SELECT. It's not tabular format, but at least it fulfills your requirement, and allows you to query and even update the result. XML support in SQL Server is very strong, just make yourself acquainted with the topic. You can start here: http://technet.microsoft.com/en-us/library/ms178107.aspx
alter procedure DisplayTable(
#tab varchar(30)
,#query varchar(max) output
)
as
BEGIN
Declare #execution varchar(max) = 'select * from ' +#tab
declare #tempStructure as table (
pk_id int identity
,ColumnName varchar(max)
,ColumnDataType varchar(max)
)
insert into
#tempStructure
select
COLUMN_NAME
,DATA_TYPE
from
INFORMATION_SCHEMA.columns
where TABLE_NAME= #tab
EXEC(#execution)
declare #ColumnCount int = (SELECT count(*) from #tempStructure)
declare #counter int = 1
while #counter <= #ColumnCount
BEGIN
IF #counter = 1
BEGIN
set #query = (SELECT ColumnName + ' ' + ColumnDataType FROM #tempStructure where pk_id= #counter)
END
IF #counter <> 1
BEGIN
set #query = #query + (SELECT ',' + ColumnName + ' ' + ColumnDataType FROM #tempStructure where #counter = pk_id)
END
set #counter = #counter + 1
END
END
When you execute the SP, you'll now get a return of the structure of the table you want.
This should hopefully get you moving.
If you want the table CONTENTS included, create yourself a loop for the entries, and append them to the #query parameter.
Remember to delimit the #query, else when you read it later on, you will not be able to restructure your table.
First of all you have to understand that you can't just store the value of a SELECTon a table in simple variable. It has to be TABLE variable which can store the value of a SELECTquery.
Try the below:
select 'name1' name, 12 age
into MyTable
union select 'name2', 15 union
select 'name3', 19
--declaring the table variable and selecting out of it..
declare #QueryResult table(name varchar(30), age int)
insert #QueryResult exec DisplayTable 'MyTable'
select * from #QueryResult
Hope this helps!