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 |
|
<compound_statement> |
Statement or block executed as long as <condition> is |
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
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