This document describes the functions available in X-Query. Many of them are defined in XPath with the same syntax and semantics. Please refer to the XPath specification for a more detailed description. Functions that are not present in XPath are marked with an asterisk. Some of the functions that are present in XPath are not implemented in X-Query, but you can extend the functionality of X-Query by writing server extensions implementing the desired function. These extensions can then be registered within the database server so that they are available for all further queries.
| Category | Function | Short Description |
|---|---|---|
| Type conversion | boolean() |
convert argument to a Boolean value |
number() |
convert argument to a number | |
string() |
convert argument to a string | |
| Arithmetic functions | ceiling() |
return the smallest integer that is greater than or equal to the argument's numeric value |
floor() |
return the largest integer that is less than or equal to the argument's numeric value | |
round() |
return the integer that is closest to the argument's numeric value | |
| String functions | starts-with() |
test whether one string starts with another string |
| Aggregation | avg() * |
return the average value of a set of numeric values that the argument's node set contain |
count() |
return the number of nodes present in the argument's node set | |
min() * |
return the smallest value of a set of numeric values that the argument's node set contain | |
max() * |
return the largest value of a set of numeric values that the argument's node set contain | |
sum() |
calculate the total of a set of numeric values that the argument's node set contain | |
| Node Names | name() |
return a qualified name representing the name of a node |
| Boolean functions | false() |
return the Boolean value "false" |
not() |
return the negated value of its argument | |
true() |
return the Boolean value "true" | |
| Context information | last() |
return the position number of the last node in the list |
position() |
return the position number of the context node | |
| Analysis | ino:explain() * |
return query execution plan |
