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* Add multi-character TRIM function * Follow Adriano's suggestion Co-authored-by: Adriano dos Santos Fernandes <529415+asfernandes@users.noreply.github.com> --------- Co-authored-by: Dmitry Yemanov <dyemanov@users.noreply.github.com> Co-authored-by: Adriano dos Santos Fernandes <529415+asfernandes@users.noreply.github.com>
49 lines
1.4 KiB
Plaintext
49 lines
1.4 KiB
Plaintext
SQL Language Extension: TRIM
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Function:
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Remove leading, trailing or both substring from a string.
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Author:
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Adriano dos Santos Fernandes <adrianosf@uol.com.br>
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Format:
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<trim function> ::=
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TRIM <left paren> [ [ <trim specification> ] [ <trim character> ] FROM ] <value expression> <right paren>
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<trim specification> ::=
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LEADING
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| TRAILING
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| BOTH
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<trim character> ::=
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<value expression>
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<multi-character trim function> ::=
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{ BTRIM | LTRIM | RTRIM } <left paren> <value expression> [ <comma> <trim character> ] <right paren>
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Syntax Rules:
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1) If <trim specification> is not specified, BOTH is assumed.
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2) If <trim character> is not specified, ' ' is assumed.
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3) If <trim specification> and/or <trim character> is specified, FROM should be specified.
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4) If <trim specification> and <trim character> is not specified, FROM should not be specified.
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5) multi-character trim function accepts a sequence of characters as the second argument and will remove all
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leading, trailing, or both occurrences of any of these characters, regardless of their ordering.
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Examples:
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A)
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select
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rdb$relation_name, trim(leading 'RDB$' from rdb$relation_name)
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from rdb$relations
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where rdb$relation_name starting with 'RDB$';
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B)
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select
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trim(rdb$relation_name) || ' is a system table'
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from rdb$relations
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where rdb$system_flag = 1;
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C)
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select
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ltrim('baobab is a tree', 'aboe')
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from rdb$database;
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