IF (criteria)
block
[ELSE
block]
END
IF statement
An IF statement evaluates a condition and executes either one of two statements depending on the result.
You can nest IF statements to create complex branching logic.
A dependent ELSE statement will execute its statement only if the IF statement evaluates to false
.
Usage
Example IF statement
IF ( var1 = 'North America')
BEGIN
...statement...
END ELSE
BEGIN
...statement...
END
The criteria can be any valid Boolean expression or an IS DISTINCT FROM
predicate referencing row values.
The IS DISTINCT FROM
extension uses the following syntax:
rowVal IS [NOT] DISTINCT FROM rowValOther
Where rowVal
and rowValOther
are references to row value group.
This would typically be used in instead of update triggers on views to quickly determine if the row values are changing:
Example: IS DISTINCT FROM IF statement
IF ( "new" IS DISTINCT FROM "old")
BEGIN
...statement...
END
IS DISTINCT FROM
considers null values equivalent and never produces an UNKNOWN value.
Tip
|
Null values should be considered in the criteria of an IF statement.
IS NULL criteria can be used to detect the presence of a null value.
|