XQuery

Comparing Strings

Several functions, summarized in Table 17-1, are available for comparing and matching strings.

Table 17-1. Functions that compare strings

Name	Description
compare	Compares two strings, optionally based on a collation
starts-with	Determines whether a string starts with another string
ends-with	Determines whether a string ends with another string
contains	Determines whether a string contains another string
matches	Determines whether a string matches a regular expression

Comparing Entire Strings

Strings can be compared using the comparison operators: =, !=, >, <, >=, and <=. For example, "abc" < "def" evaluates to true.

The comparison operators use the default collation, as described in "Collations," later in this chapter. You can also use the compare function, which fulfills the same role as the comparison operators but allows you to explicitly specify a collation. The compare function accepts two string arguments and returns one of the values −1, 0, or 1 depending on which argument is greater.

Determining Whether a String Contains Another String

Three functions test whether a string contains the characters of another string. They are the contains, starts-with, and ends-with functions. Each of them returns a Boolean value and takes two strings as arguments: the first is the containing string being tested, and the second is the contained string. Table 17-2 shows some examples of these functions.

contains-word

You may be interested to know whether a ...