119 lines
3.0 KiB
MySQL
119 lines
3.0 KiB
MySQL
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-- Taken from http://developer.postgresql.org/pgdocs/postgres/plpgsql-porting.html#PLPGSQL-PORTING-APPENDIX
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--
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-- instr functions that mimic Oracle's counterpart
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-- Syntax: instr(string1, string2, [n], [m]) where [] denotes optional parameters.
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--
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-- Searches string1 beginning at the nth character for the mth occurrence
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-- of string2. If n is negative, search backwards. If m is not passed,
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-- assume 1 (search starts at first character).
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--
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CREATE FUNCTION instr(varchar, varchar) RETURNS integer AS $$
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DECLARE
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pos integer;
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BEGIN
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pos:= instr($1, $2, 1);
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RETURN pos;
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END;
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$$ LANGUAGE plpgsql STRICT IMMUTABLE;
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CREATE FUNCTION instr(string varchar, string_to_search varchar, beg_index integer)
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RETURNS integer AS $$
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DECLARE
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pos integer NOT NULL DEFAULT 0;
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temp_str varchar;
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beg integer;
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length integer;
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ss_length integer;
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BEGIN
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IF beg_index > 0 THEN
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temp_str := substring(string FROM beg_index);
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pos := position(string_to_search IN temp_str);
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IF pos = 0 THEN
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RETURN 0;
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ELSE
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RETURN pos + beg_index - 1;
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END IF;
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ELSE
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ss_length := char_length(string_to_search);
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length := char_length(string);
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beg := length + beg_index - ss_length + 2;
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WHILE beg > 0 LOOP
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temp_str := substring(string FROM beg FOR ss_length);
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pos := position(string_to_search IN temp_str);
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IF pos > 0 THEN
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RETURN beg;
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END IF;
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beg := beg - 1;
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END LOOP;
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RETURN 0;
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END IF;
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END;
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$$ LANGUAGE plpgsql STRICT IMMUTABLE;
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CREATE FUNCTION instr(string varchar, string_to_search varchar,
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beg_index integer, occur_index integer)
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RETURNS integer AS $$
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DECLARE
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pos integer NOT NULL DEFAULT 0;
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occur_number integer NOT NULL DEFAULT 0;
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temp_str varchar;
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beg integer;
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i integer;
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length integer;
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ss_length integer;
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BEGIN
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IF beg_index > 0 THEN
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beg := beg_index;
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temp_str := substring(string FROM beg_index);
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FOR i IN 1..occur_index LOOP
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pos := position(string_to_search IN temp_str);
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IF i = 1 THEN
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beg := beg + pos - 1;
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ELSE
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beg := beg + pos;
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END IF;
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temp_str := substring(string FROM beg + 1);
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END LOOP;
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IF pos = 0 THEN
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RETURN 0;
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ELSE
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RETURN beg;
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END IF;
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ELSE
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ss_length := char_length(string_to_search);
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length := char_length(string);
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beg := length + beg_index - ss_length + 2;
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WHILE beg > 0 LOOP
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temp_str := substring(string FROM beg FOR ss_length);
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pos := position(string_to_search IN temp_str);
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IF pos > 0 THEN
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occur_number := occur_number + 1;
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IF occur_number = occur_index THEN
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RETURN beg;
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END IF;
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END IF;
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beg := beg - 1;
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END LOOP;
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RETURN 0;
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END IF;
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END;
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$$ LANGUAGE plpgsql STRICT IMMUTABLE;
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