What would be the best approach in SQL Server 2008 to select something that can contain 10 list of data, then compare that data with a specific value in one of it's columns
So something like this below
SELECT bType FROM WORK_STATION WHERE nFileId = 123456789
Which could return either 1 - 10 values MAX (will return at least one value). Then to compare the data from that SQL statement above that we just selected to a specific value to something like
if bType = 1
--DO something
What is the best approach of doing something like this?
declare #table as table(btype int)
declare #btype int
insert into #table
SELECT bType FROM WORK_STATION WHERE nFileId = 123456789
while(exists(select top 1 'x' from #table)) --as long as #table contains records continue
begin
select top 1 #btype = btype from #table
if(#btype = 10)
print 'something'
delete top (1) from #table --remove the previously processed row. also ensures no infinite loop
end
I think you can use SP to declare variables and then compare it with the resultset, if you know that you have only 10 values you can use temp table and insert 10 values.
I hope this is helpful.
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
Wasn't sure how to title the question but hopefully this makes sense :)
I have a table (OldTable) with an index and a column of comma separated lists. I'm trying to split the strings in the list column and create a new table with the indexes coupled with each of the sub strings of the string it was connected to in the old table.
Example:
OldTable
index | list
1 | 'a,b,c'
2 | 'd,e,f'
NewTable
index | letter
1 | 'a'
1 | 'b'
1 | 'c'
2 | 'd'
2 | 'e'
2 | 'f'
I have created a function that will split the string and return each sub string as a record in a 1 column table as so:
SELECT * FROM Split('a,b,c', ',', 1)
Which will result in:
Result
index | string
1 | 'a'
1 | 'b'
1 | 'c'
I was hoping that I could use this function as so:
SELECT * FROM Split((SELECT * FROM OldTable), ',')
And then use the id and string columns from OldTable in my function (by re-writing it slightly) to create NewTable. But I as far as I understand sending tables into the function doesn't work as I get: "Subquery returned more than 1 value. ... not premitted ... when the subquery is used as an expression."
One solution I was thinking of would be to run the function, as is, on all the rows of OldTable and insert the result of each call into NewTable. But I'm not sure how to iterate each row without a function. And I can't send tables into the a function to iterate so I'm back at square one.
I could do it manually but OldTable contains a few records (1000 or so) so it seems like automation would be preferable.
Is there a way to either:
Iterate over OldTable row by row, run the row through Split(), add the result to NewTable for all rows in OldTable. Either by a function or through regular sql-transactions
Re-write Split() to take a table variable after all
Get rid of the function altogether and just do it in sql transactions?
I'd prefer to not use procedures (don't know if there is a solutions with them either) mostly because I don't want the functionality inside of the DB to be exposed to the outside. If, however that is the "best"/only way to go I'll have to consider it. I'm quite (read very) new to SQL so it might be a needless worry.
Here is my Split() function if it is needed:
CREATE FUNCTION Split (
#string nvarchar(4000),
#delimitor nvarchar(10),
#indexint = 0
)
RETURNS #splitTable TABLE (id int, string nvarchar(4000) NOT NULL) AS
BEGIN
DECLARE #startOfSubString smallint;
DECLARE #endOfSubString smallint;
SET #startOfSubString = 1;
SET #endOfSubString = CHARINDEX(#delimitor, #string, #startOfSubString);
IF (#endOfSubString <> 0)
WHILE #endOfSubString > 0
BEGIN
INSERT INTO #splitTable
SELECT #index, SUBSTRING(#string, #startOfSubString, #endOfSubString - #startOfSubString);
SET #startOfSubString = #endOfSubString+1;
SET #endOfSubString = CHARINDEX(#delimitor, #string, #startOfSubString);
END;
INSERT INTO #splitTable
SELECT #index, SUBSTRING(#string, #startOfSubString, LEN(#string)-#startOfSubString+1);
RETURN;
END
Hope my problem and attempt was explained and possible to understand.
You are looking for cross apply:
SELECT t.index, s.item
FROM OldTable t CROSS APPLY
(dbo.split(t.list, ',')) s(item);
Inserting in the new table just requires an insert or select into clause.
I have a table that looks like this:
memberno(int)|member_mouth (varchar)|Inspected_Date (varchar)
-----------------------------------------------------------------------------
12 |'1;2;3;4;5;6;7' |'12-01-01;12-02-02;12-03-03' [7 members]
So by looking at how this table has been structured (poorly yes)
The values in the member_mouth field is a string that is delimited by a ";"
The values in the Inspected_Date field is a string that is delimited by a ";"
So - for each delimited value in member_mouth there is an equal inspected_date value delimited inside the string
This table has about 4Mil records, we have an application written in C# that normalizes the data and stores it in a separate table. The problem now is because of the size of the table it takes a long time for this to process. (the example above is nothing compared to the actual table, it's much larger and has a couple of those string "array" fields)
My question is this: What would be the best and fastest way to normilize this data in MSSQL proc? let MSSQL do the work and not a C# app?
The best way will be SQL itself. The way followed in the below code is something which worked for me well with 2-3 lakhs of data.
I am not sure about the below code when it comes to 4 Million, but may help.
Declare #table table
(memberno int, member_mouth varchar(100),Inspected_Date varchar(400))
Insert into #table Values
(12,'1;2;3;4;5;6;7','12-01-01;12-02-02;12-03-03;12-04-04;12-05-05;12-07-07;12-08-08'),
(14,'1','12-01-01'),
(19,'1;5;8;9;10;11;19','12-01-01;12-02-02;12-03-03;12-04-04;12-07-07;12-10-10;12-12-12')
Declare #tableDest table
(memberno int, member_mouth varchar(100),Inspected_Date varchar(400))
The table will be like.
Select * from #table
See the code from here.
------------------------------------------
Declare #max_len int,
#count int = 1
Set #max_len = (Select max(Len(member_mouth) - len(Replace(member_mouth,';','')) + 1)
From #table)
While #count <= #max_len
begin
Insert into #tableDest
Select memberno,
SUBSTRING(member_mouth,1,charindex(';',member_mouth)-1),
SUBSTRING(Inspected_Date,1,charindex(';',Inspected_Date)-1)
from #table
Where charindex(';',member_mouth) > 0
union
Select memberno,
member_mouth,
Inspected_Date
from #table
Where charindex(';',member_mouth) = 0
Delete from #table
Where charindex(';',member_mouth) = 0
Update #table
Set member_mouth = SUBSTRING(member_mouth,charindex(';',member_mouth)+1,len(member_mouth)),
Inspected_Date = SUBSTRING(Inspected_Date,charindex(';',Inspected_Date)+1,len(Inspected_Date))
Where charindex(';',member_mouth) > 0
Set #count = #count + 1
End
------------------------------------------
Select *
from #tableDest
Order By memberno
------------------------------------------
Result.
You can take a reference here.
Splitting delimited values in a SQL column into multiple rows
Do it on SQl server side, if possible a SSIS package would be great.
Is there a way to combine assigning a value to a variable and Selecting a column in sql. I need to compute and select a column in a table based on the variable. The variable's value changes based on another column in the table.
var #BeginValue
Columns in table : ReducedBy
My initial begin value is stored in #BeginValue. The table has reducedBy which is a factor by which my begin value should be reduced. So when i select, beginvalue for the first recored would be #BeginValue and the #EndValue should be #BeginValue = #BeginValue - reducedBy. It continues like this, as many times as the number of records in my table.
Result set must be like this:
#Begin = 10
Begin End ReducedBy
10 8 2
8 6 2
6 5 1
Is there a way with which i can achieve this without using a cursor or with multiple update statements.
You can't assign in a query that returns a result set. The closest you can get is to store the result in a table variable. Then you can both do computations against that table, and return it as a result set:
-- Store results in table variable
declare #tbl table (id int, col1 int, ...)
insert #tbl
(id, col1, ...)
select id
, col1
, ...
from ... your query here ...
-- Assign variable
select #YourVariable = ... your computation here ...
from #tbl
-- Return result set
select *
from #tbl
If your question is
Can I do..
SELECT #a = field, field2 from table
and get a resultset and set the value of #a?
Then the answer is no, not in a single statement.
I want to copy data from one table (rawdata, all columns are VARCHAR) to another table (formatted with corresponding column format).
For copying data from the rawdata table into formatted table, I'm using cursor in order to identify which row is affected. I need to log that particular row in an error log table, skip it, and continue copying remaining rows.
It takes more time to copying. Is there any other way to achieve this?
this is my query
DECLARE #EntityId Varchar(16) ,
#PerfId Varchar(16),
#BaseId Varchar(16) ,
#UpdateStatus Varchar(16)
DECLARE CursorSample CURSOR FOR
SELECT EntityId, PerfId, BaseId, #UpdateStatus
FROM RawdataTable
--Returns 204,000 rows
OPEN CursorSample
FETCH NEXT FROM CursorSample INTO #EntityId,#PerfId,#BaseId,#UpdateStatus
WHILE ##FETCH_STATUS = 0
BEGIN
BEGIN TRY
--try insertting row in formatted table
Insert into FormattedTable
(EntityId,PerfId,BaseId,UpdateStatus)
Values
(Convert(int,#EntityId),
Convert(int,#PerfId),
Convert(int,#BaseId),
Convert(int,#UpdateStatus))
END TRY
BEGIN CATCH
--capture Error EntityId in errorlog table
Insert into ERROR_LOG
(TableError_Message,Error_Procedure,Error_Log_Time)
Values
(Error_Message()+#EntityId,’xxx’, GETDATE())
END CATCH
FETCH NEXT FROM outerCursor INTO #EntityId, #BaseId
END
CLOSE CursorSample
DEALLOCATE CursorSampler –cleanup CursorSample
You should just be able to use a INSERT INTO statement to put the records directly into the formatted table. INSERT INTO will perform much better than using a cursor.
INSERT INTO FormattedTable
SELECT
CONVERT(int, EntityId),
CONVERT(int, PerfId),
CONVERT(int, BaseId),
CONVERT(int, UpdateStatus)
FROM RawdataTable
WHERE
IsNumeric(EntityId) = 1
AND IsNumeric(PerfId) = 1
AND IsNumeric(BaseId) = 1
AND IsNumeric(UpdateStatus) = 1
Note that IsNumeric can sometimes return 1 for values that will then fail on CONVERT. For example, IsNumeric('$e0') will return 1, so you may need to create a more robust user defined function for determining if a string is a number, depending on your data.
Also, if you need a log of all records that could not be moved into the formatted table, just modify the WHERE clause:
INSERT INTO ErrorLog
SELECT
EntityId,
PerfId,
BaseId,
UpdateStatus
FROM RawdataTable
WHERE
NOT (IsNumeric(EntityId) = 1
AND IsNumeric(PerfId) = 1
AND IsNumeric(BaseId) = 1
AND IsNumeric(UpdateStatus) = 1)
EDIT
Rather than using IsNumeric directly, it may be better to create a custom UDF that will tell you if a string can be converted to an int. This function worked for me (albeit with limited testing):
CREATE FUNCTION IsInt(#value VARCHAR(50))
RETURNS bit
AS
BEGIN
DECLARE #number AS INT
DECLARE #numeric AS NUMERIC(18,2)
SET #number = 0
IF IsNumeric(#value) = 1
BEGIN
SET #numeric = CONVERT(NUMERIC(18,2), #value)
IF #numeric BETWEEN -2147483648 AND 2147483647
SET #number = CONVERT(INT, #numeric)
END
RETURN #number
END
GO
The updated SQL for the insert into the formatted table would then look like this:
INSERT INTO FormattedTable
SELECT
CONVERT(int, CONVERT(NUMERIC(18,2), EntityId)),
CONVERT(int, CONVERT(NUMERIC(18,2), PerfId)),
CONVERT(int, CONVERT(NUMERIC(18,2), BaseId)),
CONVERT(int, CONVERT(NUMERIC(18,2), UpdateStatus))
FROM RawdataTable
WHERE
dbo.IsInt(EntityId) = 1
AND dbo.IsInt(PerfId) = 1
AND dbo.IsInt(BaseId) = 1
AND dbo.IsInt(UpdateStatus) = 1
There may be a little weirdness around handling NULLs (my function will return 0 if NULL is passed in, even though an INT can certainly be null), but that can be adjusted depending on what is supposed to happen with NULL values in the RawdataTable.
You can put a WHERE clause in your cursor definition so that only valid records are selected in the first place. You might need to create a function to determine validity, but it should be faster than looping over them.
Actually, you might want to create a temp table of the invalid records, so that you can log the errors, then define the cursor only on the rows that are not in the temp table.
Insert into will work much more better than Cursor.
As Cursor work solely in Memory of your PC and slows down the optimization of SQL Server. We should avoid using Cursors but (of course) there are situations where usage of Cursor cannot be avoided.