# 22. Virtuoso Functions Guide - if

Chapter Contents | Prev | Next
Keyword Search:
www.openlinksw.com
docs.openlinksw.com
Book Home
Contents
Preface
Virtuoso Functions Guide
Administration
Aggregate Functions
Array Manipulation
BPEL APIs
Backup
Compression
Cursor
Date & Time Manipulation
Debug
Dictionary Manipulation
Encoding & Decoding
File Manipulation
Free Text
Hashing / Cryptographic
LDAP
Locale
Mail
Miscellaneous
Number
Remote SQL Data Source
Replication
SOAP
SQL
String
Transaction
Type Mapping
UDDI
User Defined Types & The CLR
Virtuoso Java PL API
Virtuoso Server Extension Interface (VSEI)
Web Server & Internet
XML
XPATH & XQUERY
and
append
assign
avg
boolean
ceiling
concat
contains
count
create-attribute
create-comment
create-element
create-pi
current
distinct
doc
document
document-literal
empty
ends-with
every
except
false
filter
floor
fn:collection
for
format-number
function-available
generate-id
id
if
intersect
is_after()
is_before()
key
lang
last
let
list()
local-name
max
min
name
namespace-uri
normalize-space
not
number
or
position
processxquery
processxslt
processxsql
progn()
replace()
round
serialize
shallow
some
starts-with
string
string-length
substring
substring-after
substring-before
sum
system-property
text_contains()
translate
true
tuple()
union
unordered
unparsed-entity-uri
urlify
xmlview
Functions Index

## if

If the boolean value is true then calculates one expression, otherwise calculates another expression.
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 expessions, 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

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!'

See Also

and() or()