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SQL Language Extension: TRIM
Function:
Remove leading, trailing or both substring from a string.
Author:
Adriano dos Santos Fernandes <adrianosf@uol.com.br>
Format:
<trim function> ::=
TRIM <left paren> [ [ <trim specification> ] [ <trim character> ] FROM ] <value expression> <right paren>
<trim specification> ::=
LEADING
| TRAILING
| BOTH
<trim character> ::=
<value expression>
Syntax Rules:
1) If <trim specification> is not specified, BOTH is assumed.
2) If <trim character> is not specified, ' ' is assumed.
3) If <trim specification> and/or <trim character> is specified, FROM should be specified.
4) If <trim specification> and <trim character> is not specified, FROM should not be specified.
Examples:
A)
select
rdb$relation_name, trim(leading 'RDB$' from rdb$relation_name)
from rdb$relations
where rdb$relation_name starting with 'RDB$';
B)
select
trim(rdb$relation_name) || ' is a system table'
from rdb$relations
where rdb$system_flag = 1;
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