WHILE ... DO

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Performs the statement or block following DO as long as the specified condition is TRUE. Available in triggers and stored procedures.

WHILE (<condition>) DO 
<<compound_statement>>
Argument Description

<condition>

Boolean expression tested before each execution of the statement or block following DO

<compound_statement>

Statement or block executed as long as <condition> is TRUE

Description: WHILE DO is a looping statement that repeats a statement or block of statements as long as a condition is true. The condition is tested at the start of each loop.

Example: The following procedure, from an isql script, uses a WHILE DO loop to compute the sum of all integers from one up to the input parameter:

CREATE PROCEDURE SUM_INT (I INTEGER) RETURNS (S INTEGER)
AS
BEGIN
S = 0;
WHILE (I > 0) DO
BEGIN
S = S + I;
I = I - 1;
END
END;

If this procedure is called from isql with the command:

EXECUTE PROCEDURE SUM_INT 4;

then the results will be:

S
==========
10

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