 | --
-- Oracleのものと同じ動作をする instr関数
-- 構文 :instr(string1,string2,[n],[m]) ただし、[]は省略可能なパラメータ
--
-- string1内のn番目の文字からm番目の文字まででstring2を探します。
-- nが負の場合、逆方向に検索します。mが渡されなかった場合は、1と
-- みなします(最初の文字から検索を始めます)。
--
CREATE FUNCTION instr(varchar, varchar) RETURNS integer AS $$
DECLARE
pos integer;
BEGIN
pos:= instr($1, $2, 1);
RETURN pos;
END;
$$ LANGUAGE plpgsql STRICT IMMUTABLE;
CREATE FUNCTION instr(string varchar, string_to_search varchar, beg_index integer)
RETURNS integer AS $$
DECLARE
pos integer NOT NULL DEFAULT 0;
temp_str varchar;
beg integer;
length integer;
ss_length integer;
BEGIN
IF beg_index > 0 THEN
temp_str := substring(string FROM beg_index);
pos := position(string_to_search IN temp_str);
IF pos = 0 THEN
RETURN 0;
ELSE
RETURN pos + beg_index - 1;
END IF;
ELSE
ss_length := char_length(string_to_search);
length := char_length(string);
beg := length + beg_index - ss_length + 2;
WHILE beg > 0 LOOP
temp_str := substring(string FROM beg FOR ss_length);
pos := position(string_to_search IN temp_str);
IF pos > 0 THEN
RETURN beg;
END IF;
beg := beg - 1;
END LOOP;
RETURN 0;
END IF;
END;
$$ LANGUAGE plpgsql STRICT IMMUTABLE;
CREATE FUNCTION instr(string varchar, string_to_search varchar,
beg_index integer, occur_index integer)
RETURNS integer AS $$
DECLARE
pos integer NOT NULL DEFAULT 0;
occur_number integer NOT NULL DEFAULT 0;
temp_str varchar;
beg integer;
i integer;
length integer;
ss_length integer;
BEGIN
IF beg_index > 0 THEN
beg := beg_index;
temp_str := substring(string FROM beg_index);
FOR i IN 1..occur_index LOOP
pos := position(string_to_search IN temp_str);
IF i = 1 THEN
beg := beg + pos - 1;
ELSE
beg := beg + pos;
END IF;
temp_str := substring(string FROM beg + 1);
END LOOP;
IF pos = 0 THEN
RETURN 0;
ELSE
RETURN beg;
END IF;
ELSE
ss_length := char_length(string_to_search);
length := char_length(string);
beg := length + beg_index - ss_length + 2;
WHILE beg > 0 LOOP
temp_str := substring(string FROM beg FOR ss_length);
pos := position(string_to_search IN temp_str);
IF pos > 0 THEN
occur_number := occur_number + 1;
IF occur_number = occur_index THEN
RETURN beg;
END IF;
END IF;
beg := beg - 1;
END LOOP;
RETURN 0;
END IF;
END;
$$ LANGUAGE plpgsql STRICT IMMUTABLE; |
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