This can be defined as a memory are in which result of a query is started. If you want to use a multiple raw select in a stored procedure you need to create a cursor.
SQL Server is very good at handling sets of data. For example, you can use a single UPDATE statement to update many rows of data. There are times when you want to loop through a series of rows a perform processing for each row. In this case you can use a cursor.
Step 01
Declare the Cursor
When you declare the cursor, we tell the server to allocate memory for the query, which is to be executed.
Step 02
Open the Cursor
The Query actually gets executed a results set is created and the cursor points to the first Record.
Step 03
Fetch the Records one by one from the results set using a loop.
Step 04
Close the Cursor
Step 05(optional)
De-allocates the memory occupied by the Cursor.
Eg:1
DECLARE CUR1 CURSOR FOR SELECT * FROM EMPLOYEES WHERE DEPTNO=20
OPEN CUR1
FETCH NEXT FROM CUR1
WHILE @@FETCH_STATUS =0
BEGIN
FETCH NEXT FROM CUR1
END
CLOSE CUR1
DEALLOCATE CUR1
Eg:2
DECLARE @EN VARCHAR(20), @
DECLARE CUR2 CURSOR FOR SELECT ENAME,SAL FROM EMPLOYEES WHERE DEPNO=20
OPEN CUR2
FETCH NEXT FROM CUR2 INTO @EN, @S
WHILE @@FETCH_STATUS=0
BEGIN
PRINT @EN
PRINT @S
FETCH NEXT FROM CUR2 INTO @EN, @S
END
CLOSE CUR2
DEALLOCATE CUR2
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