I have this requirement to be implemented in a stored procedure. Dynamically query the database to get the count of a table, store it in a t-sql variable and then take some decisions based on that.
This is the stored procedure that i am working on . This is throwing some errors as i don't think there is a simple way of assigning the result of a tsql dynamic query to a variable.
CREATE PROCEDURE test
AS
BEGIN
DECLARE #sql VARCHAR(255)
DECLARE #cnt int
SET #sql = 'SELECT COUNT(1) FROM myTable'
SET #cnt = EXEC(#sql)
IF (#cnt > 0)
PRINT 'A'
ELSE
PRINT 'B'
END
GO
Could someone tell me if there is a simpler way of achieving this using T-SQL ?
Thanks.
alternative:
declare #tablename varchar(512) = 'sometable'
declare #sql nvarchar(512) = 'set #count = (select count(*) from ' + #tablename + ')'
declare #count int
execute sp_executesql #sql, N'#count int output', #count=#count output
select case when #count > 0 then 'A' else 'B' end
Try this:
SET #sql = 'SELECT #cnt = COUNT(1) FROM myTable'
EXEC(#sql)
Related
I want to execute a dynamic query to get the affected row count. But SQL Result pane returns me the result after executing it. How to avoid returning the columns. I tried the below way.
DECLARE #Command NVARCHAR(MAX)= 'SELECT * FROM Product WHERE ID = 12'
DECLARE #Count AS INT
EXEC sp_executesql #Command, N'#C INT OUTPUT', #C=#Count OUTPUT
IF (#Count > 0)
BEGIN
EXECUTE (#Command)
END
ELSE
BEGIN
DECLARE #CatalogProduct VARCHAR(MAX) = 'SELECT p.ManufactureCode,p.PartNo,p.Size,p.ID AS ProductID,p.Name ,p.ParentProductID,p.BasePrice FROM Product.Product p WHERE p.ThruDate > GETDATE() '+#Where
EXECUTE (#CatalogProduct)
END
END
I want to avoid returning the null column set from the above attached image.
You can turn off the display, but I think a better approach is to get the count you want directly:
DECLARE #Command NVARCHAR(MAX)= 'SELECT * FROM Product WHERE ID = 12';
DECLARE #count AS INT;
DECLARE #CntCommand NVARCHAR(MAX);
SET #CntCommand = 'SELECT #count = COUNT(*) FROM (' + #Command + ') x)';
EXEC sp_executesql #CntCommand, N'#count INT OUTPUT', #count=#count OUTPUT;
Why not simply?
IF (SELECT COUNT(*) FROM Product = 12) > 0 BEGIN...
I can't see why the COUNT statement needs to be dynamic; there's nothing dynamic about it.
Also, having the SQL '... WHERE p.ThruDate > GETDATE() '+#Where is a terrible idea. If #where is a parameter it'll be wide open to SQL injection.
Try this one. Returns number of rows affected by the last query:
select ##Rowcount
DECLARE #Command NVARCHAR(MAX)= 'SELECT * FROM Product WHERE ID = 12'
DECLARE #CountCommand NVARCHAR(MAX)= 'SELECT #Count=count(1) FROM Product WHERE ID = 12'
DECLARE #Count AS INT
EXEC sp_executesql #CountCommand , N'#Count INT OUTPUT', #Count=#Count OUTPUT
IF (#Count > 0)
BEGIN
EXECUTE (#Command)
END
ELSE
BEGIN
DECLARE #CatalogProduct VARCHAR(MAX) = 'SELECT p.ManufactureCode,p.PartNo,p.Size,p.ID AS ProductID,p.Name ,p.ParentProductID,p.BasePrice FROM Product.Product p WHERE p.ThruDate > GETDATE() '+#Where
EXECUTE (#CatalogProduct)
END
END
How to pass table name dynamically to the stored procedure or a simple SQL query, then store the results in a variable?
You may looking for something like this ?
USE [master]
GO
DECLARE #sql NVARCHAR(2000)
DECLARE #TableName NVARCHAR(100) ='sys.tables'
DECLARE #RecordCount INT
SET #sql = N' SELECT #RecordCountOut = COUNT(*)
FROM ' + #TableName + ' AS t'
EXEC sp_executesql #sql, N'#RecordCountOut INT OUTPUT', #RecordCountOut = #RecordCount OUTPUT
SELECT #RecordCount
You could stored your SQL query result in this way
DECLARE #Result NVARCHAR(MAX)
SELECT #Result = COLUMN FROM TableName
however, you could use print command to check what the query return
print #Result
In Azure SQL Data Warehouse stored procedure I try to form Dynamic SQL and perform select query,I unable to fetch the resutSet
Below is code Snippet:
DECLARE #sql nvarchar(400)
DECLARE #cnt int
BEGIN
---Some Business Logic---
SELECT #sql = N'select #cnt = count(*) from '+quotename(#src_TableName)+' where warn_remarks like ''%'+ #condition +'%''';
SET #parameter = N'#cnt int OUTPUT'
EXECUTE sp_executesql #sql,#parameter,#cnt = #cnt OUTPUT
END
The Error it is showing is
"Incorrect syntax near '='",In the select query when assigning count(*) to a variable it is giving error.But the same logic is working fine in Azure SQL Database.Kindly help to solve this.
You'll need to use SET instead, because you can't set variables using SELECT in SQL DW or PDW.
DECLARE #sql nvarchar(400)
DECLARE #cnt int
BEGIN
---Some Business Logic---
SET #sql = N'SET #cnt = (select count(*) from '+quotename(#src_TableName)+' where warn_remarks like ''%'+ #condition +'%'')'; --replaced
SET #parameter = N'#cnt int OUTPUT'
EXECUTE sp_executesql #sql,#parameter,#cnt = #cnt OUTPUT
END
Select #var is not supported in Azure SQL data warehouse.
https://msdn.microsoft.com/en-us/library/ms187330.aspx
You can find workarounds https://azure.microsoft.com/en-us/documentation/articles/sql-data-warehouse-develop-variable-assignment/
Suppose I have a query stored in a variable like this (it's actually dynamically populated and more complex, but this is for demonstration purposes):
DECLARE #Query VARCHAR(1000) = 'SELECT * FROM dbo.MyTable'
Is there a way to check if the query would return any results? Something like this, but this doesn't work:
IF EXISTS (#Query)
BEGIN
-- do something
END
The only way that I can think of to do this is to put the results in a temp table and then query from that, but that is not ideal because the columns in the dynamic query can vary and I really don't need the temp table at all for any reason other than checking whether some rows would be returned. Is there a better way?
Try Executing the Dynamic query and use ##RowCount to find the existence of rows.
DECLARE #Query NVARCHAR(1000) = 'SELECT * FROM [dbo].[Mytable]',
#rowcnt INT
EXEC Sp_executesql #query
SELECT #rowcnt = ##ROWCOUNT
IF #rowcnt > 0
BEGIN
PRINT 'row present'
END
Try this:
DECLARE #Query NVARCHAR(1000) = 'SELECT #C = COUNT(*) FROM dbo.MyTable'
DECLARE #Count AS INT
EXEC sp_executesql #Query, N'#C INT OUTPUT', #C=#Count OUTPUT
IF (#Count > 0)
BEGIN
END
I know this answer is too late. but, I'm leaving this here to help someone else to use IF EXISTS with a dynamic query.
This is how you should do it with dynamic queries.
DECLARE #Query VARCHAR(MAX)
SET #Query = 'SELECT * FROM [dbo].[MyTable]'
SET #Query = 'IF EXISTS (' + #Query + ')
BEGIN
-- do something
print ''1''
END
ELSE
BEGIN
-- do something else
print ''0''
END
'
exec (#Query)
Hope this helped someone. Vote if it did :)
You can use EXEC to execute sql statement, then call ##ROWCOUNT which Returns the number of rows affected by the last statement, to check row exists in sql select stetement.
DECLARE #Query VARCHAR(1000) = 'SELECT * FROM dbo.MyTable',#hasRow int
EXEC (#Query)
SELECT #hasRow =##ROWCOUNT // Returns the number of rows affected by the last statement
PRINT #hasRow
IF #hasRow > 0
BEGIN
Print 1
END
BEGIN
Print 2
END
Hi I think that only way is to put IF EXISTS part into code of execution. My case is to stop execution in point when select affects at least one row, that is goal of IF EXISTS.
Little example that saves reading all records covering by condition to first occurence:
set nocount off;
drop table if exists #temp
go
create table #temp (idCol int identity(1,1),someText nvarchar(1))
go
insert into #temp values ('a')
go 25000
declare #query nvarchar(max)
,#resultFork bit
set #query = 'if exists (select * from #temp where idCol % 3 = 0)
set #resultFork=1
else
set #resultFork=0'
print #query
exec sp_executeSQL #query, N'#resultFork int output', #resultFork=#resultFork output
print #resultFork
/*Now U can use #resultFork in simple if condition...
if #resultFork = 1
begin
--
end
else
begin
--
end
*/
I am trying to get count of a rows with specific values in a table, and if the count is 0, then add a value in the table. This count is a local variable in stored procedure.
I am building the SQL dynamically and storing SQL statement into a nvarchar variable.
Then, using EXEC I am running this SQL as follows hoping to populate count variable.
But it's not working.
DECLARE #qry NVARCHAR(max)
DECLARE #count INT
-- building #qry will result as follows
#qry = SELECT #count = COUNT(*) FROM aTable WHERE (col1 = #col1 AND ...)
#count = EXEC #qry
IF #count = 0
BEGIN
-- carry on with adding
END
In your sql ,why you are execute your query through EXEC because of your required output is already in #count variable so it is not need in your case.
Please refer below syntax.
DECLARE #qry Numeric
DECLARE #count INT
-- building #qry will result as follows
SELECT #count = COUNT(*) FROM aTable WHERE (col1 = #col1 AND ...)
IF #count = 0
BEGIN
-- carry on with adding
END
If you are building the query dynamically, you need sp_executesql. Try something like
-- building #qry will result as follows
#qry = 'SELECT #count = COUNT(*) FROM aTable WHERE (col1 = #col1 AND ...)'
EXEC sp_executesql #qry, N'#count INT OUTPUT', #count OUTPUT;
--Do whatever you want with #count...
Source: Aaron Bertrand's answer here and sp_executesql explanation..
I think #qry needs to be a string for executing, not the result of the select, like so:
DECLARE #qry NVARCHAR(max);
DECLARE #count INT;
-- building #qry will result as follows
SET #qry = 'SELECT COUNT(*) FROM aTable WHERE (col1 = #col1 AND ...)';
SET #count = exec #qry;