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## length Function

The length function returns the length of a character string. The length function calculates the length using the UTF character set.

Syntax

    returnvalue length(source)

    source ::= any*
    returnvalue ::= integer

Semantics

source

  The input string for which the length should be determined. This argument is implicitly cast to a sequence of strings.

returnvalue

  Returns NULL if the source argument is NULL.

  Returns NULL if the source argument is an empty sequence or a sequence with more than one item.

Note:

Characters that are represented on 32 or more bits, the length is considered 1, while Java String.length() returns 2 for UTF32 chars, 4 for UTF64, etc.

Example 12-59 length Function

In this example, the length of the first name is selected from the users table.

    SELECT firstname, length(firstname) as length FROM users

Output:

     +-----------+--------+
     | firstname | length |
     +-----------+--------+
     | John      |      4 |
     | Mary      |      4 |
     | Peter     |      5 |
     +-----------+--------+