SQL cursor fetch status meaning

sql sql-server tsql database-cursor
Volkan picture Volkan · Oct 7, 2015 · Viewed 22.7k times · Source

I don't understand the meaning of following lines:

   WHILE 1 = 1 
   BEGIN
      FETCH NEXT FROM SomeCursor INTO @SomeId, @SomeOtherColumn

      IF @@FETCH_STATUS <> 0 BREAK

What are the meanings of while 1=1? and if fetch status is different than 0?

Answer

Bridge picture Bridge · Oct 7, 2015

1=1 is just a short condition which always return true, that is, loop forever (well, until you break out of it elsewhere).

As for fetch status values, as usual MSDN is your friend here. From https://msdn.microsoft.com/en-us/library/ms187308.aspx

  • 0 = The FETCH statement was successful.
  • -1 = The FETCH statement failed or the row was beyond the result set.
  • -2 = The row fetched is missing.

E.g. if you get anything other than 0, things have gone wrong, so there's no point in continuing.

On a side note, MSDN also notes that is is a legacy thing, @@FETCH_STATUS is global, and therefore where multiple cursors are being used it is not to be trusted. Instead lookup your cursor's individual fetch status value from the sys.dm_exec_cursors dynamic management function.

Related questions

How do I UPDATE from a SELECT in SQL Server?

In SQL Server, it is possible to insert rows into a table with an INSERT.. SELECT statement: INSERT INTO Table (col1, col2, col3) SELECT col1, col2, col3 FROM other_table WHERE sql = 'cool' Is it also possible to update a …

Read More
How do I perform an IF...THEN in an SQL SELECT?

How do I perform an IF...THEN in an SQL SELECT statement? For example: SELECT IF(Obsolete = 'N' OR InStock = 'Y' ? 1 : 0) AS Saleable, * FROM Product

Read More
OR is not supported with CASE Statement in SQL Server

The OR operator in the WHEN clause of a CASE statement is not supported. How can I do this? CASE ebv.db_no WHEN 22978 OR 23218 OR 23219 THEN 'WECS 9500' ELSE 'WECS 9520' END as wecs_system

Read More