SQL

Using SELECT statement to UPDATE records in SQL

Nouman Zakir — Tue, 04 Aug 2009 11:28:10 GMT

You can use SELECT statement to update records through UPDATE statement.
In the SET Clause use the SELECT statement along with desired filters to
update the records.

UPDATE tblDestination
SET tblDestination.col=value
WHERE EXISTS (
SELECT col2.value
FROM tblSource
WHERE tblSource.join_col=tblDestination.join_col
AND tblSource.constraint=value)

Using SELECT statement to INSERT records in SQL

Nouman Zakir — Tue, 04 Aug 2009 09:57:24 GMT

In INSERT statement, by replacing the VALUES clause with a SELECT statement
you can get a set of records for INSERT.

Suppose I have a table called table_A and I want to populate it with the ID, Name and
Address of table_B. The statement would look something like this:

INSERT table_A (col_id, col_name, col_address)
SELECT col_id, col_name, col_address
FROM table_B
WHERE col_city = 'karachi'

This will take the records with col_city='karachi' and load them into the
table table_A. I can use any type of SELECT statement here.
It just has to return a record set that matches the columns in the
INSERT statement. The number of columns and their data types must match
(or be implicitly convertible). I can also execute a stored procedure
that returns a record set using the EXEC command in place of the SELECT
statement.

Optional parameters in SQL Stored Procedures

Nouman Zakir — Sat, 28 Feb 2009 11:48:24 GMT

You can add optional parameters in stored procedures by setting a default value for each parameter that you want to make optional. The default value is typically NULL, but it's not necessary.

Example:

CREATE PROCEDURE dbo.mySP
@firstParam VARCHAR(32) = NULL,
@secondParam INT = NULL
AS

BEGIN

SET NOCOUNT ON
SELECT *
FROM [TableName]
WHERE
Param1 = @firstParam
AND Param2 = @secondParam

END
GO

--
EXEC dbo.mySP @firstParam ='bar', @secondParam =4
EXEC dbo.mySP @firstParam ='bar'
EXEC dbo.mySP @secondParam =4
EXEC dbo.mySP 'bar',4
EXEC dbo.mySP 'bar'
EXEC dbo.mySP
GO

DROP PROCEDURE dbo.mySP
GO

Reset table identity (reseed) in SQL Server with DBCC RESEED

Nouman Zakir — Wed, 11 Feb 2009 09:59:34 GMT

You may use DBCC CHECKIDENT to reseed (reset) the identity column of any table in SQL Server.

Example:

A table has 10 rows with 10 as last identity. The next record will automatically genrate 11, to start the new identity use the follwing T SQL query in query analyzer.

DBCC CHECKIDENT (tableName, reseed, 15)

To set the seed to zero use the following T SQL query in query analyzer.

DBCC CHECKIDENT (tableName, reseed, 0)

Avoid using a value lower than the current value, doing this will violate the uniqueness contrant in case of new entries.

Find text in SQL stored procedures

Nouman Zakir — Mon, 02 Feb 2009 06:43:08 GMT

Method to retrieve every text inside the stored procedures of a database

SELECT B.Name, *
FROM syscomments A INNER JOIN sysobjects B
ON A.id = B.id
WHERE A.text like '%tblNames%'