String slicing

Returns a range of characters from a string.

Syntax

<string>[<start>:<end>]
<string>[:<end>]
<string>[<start>:]
<string>[:]

Arguments

<string>

An expression that evaluates to a STRING.

<start>

The zero-based character position at which the result starts. A negative value counts backward from the end of the string. When omitted or NULL, the slice starts at the first character.

<end>

The zero-based character position at which the result stops. The character at this position is not included. A negative value counts backward from the end of the string. When omitted or NULL, the slice continues through the final character.

Returns

Returns a STRING. ScopeDB counts Unicode characters rather than UTF-8 bytes. Bounds outside the string are clamped to its valid range. If the normalized start position is greater than or equal to the end position, the result is an empty string. A NULL input string returns NULL.

ScopeQL does not provide a substr() function or support a step value in slice syntax.

Examples

SELECT
    'testing 1 2 3'[8:11] AS part,
    'mystring'[-3:] AS tail,
    '零1二3四5'[1:4] AS unicode_part;

+------+------+--------------+
| part | tail | unicode_part |
+------+------+--------------+
| 1 2  | ing  | 1二3          |
+------+------+--------------+