WHILE ... DO

Use for conditional looping.

Syntax

<while_do_loop> ::=

  WHILE (<condition>) DO <compound_statement>

<compound_statement> ::= {<block> | <statement>}

A WHILE statement implements a loop, the <compound_statement> will be executed as long as the <condition> evaluates to TRUE. This means it's possible the statements in the loop aren't executed at all.

The loop will end when <condition> evaluates to FALSE or UNKNOWN.

The loop can be broken without evaluating the condition with a LEAVE statement or exited with a EXIT or RETURN statement. The next iteration can be forced using a CONTINUE statement.

See Also

Example

EXECUTE UDSBLOCK

AS

BEGIN

  I = 1;

  WHILE (i < 10)

  DO BEGIN

       i = i + 1;

       IF (Math.Mod(i, 2) = 0) /* check for even numbers, skip the loop if even */

       THEN CONTINUE;

       ELSE BEGIN

              /* do stuff */

            END

     END

END