Name
if — If the boolean value is true then calculates one expression, otherwise calculates another expression.
Synopsis
any
if
(
|
test boolean , |
| then_branch any , | |
else_branch
any
); |
Description
This function calculates the value of test
argument.
If the value is true, the function calculates the then_branch
expression and returns its value.
If the value is false, the function calculates the else_branch
expression and returns its value.
Note that unlike other programming languages, else_branch
is required argument, not optional.
This function is used in the implementation of "IF" control operator in XQUERY, so you will probably use that operator in XQUERY expressions, not the function. This function may be useful in XPATH expressions and in XSLT stylesheets. It is not a part of library of standard XQUERY 1.0 functions.
Parameters
test
Boolean value used to choose an expression to execute
then_branch
Expression which is calculated if
test
argument is true
else_branch
Expression which is calculated if
test
argument is false
Return Types
Any
Examples
Example 24.593.
These two expressions are equivalent, but first may be used in any XPATH while second is written in XQUERY syntax:
if (2 * 2 = 4, 'I think so', 'Unbelievable!') IF 2 * 2 = 4 THEN 'I think so' ELSE 'Unbelievable!'