SQL/Server Cursor - Example of reason to use

[Aluminum]

I cannot find an example online for a reason WHY you would need a cursor instead of an update statement. Does anyone have an example of a problem that can only be solved by using a cursor?

 

[hmckillop]

Tons of reasons when you could use a cursor, but generally you can replace them with derived tables, table variables or just rethinking your problem.

A sample example of when you could use a cursor is to loop through every table in a db outputting the contents. (I know you are likely never to want to do this but just giving an example as requested)

e.g.

DECLARE @tablename varchar(255), @sSQL varchar(2000)
	
DECLARE c1 CURSOR READ_ONLY
FOR
select name from sys.sysobjects where xtype = 'U'

OPEN c1

FETCH NEXT FROM c1
INTO @tablename

WHILE @@FETCH_STATUS = 0
BEGIN

	select @sSQL = 'SELECT * FROM ' + @tablename
        exec (@sSQL)

	FETCH NEXT FROM c1
	INTO @tablename

END

CLOSE c1
DEALLOCATE c1

Its just an example which cant "be replaced by a simple update"



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