CREATE OR REPLACE FUNCTION GET_STRING_01_FC(P_STRING VARCHAR2，P_SEPARATOR VARCHAR2)
RETURN VARCHAR2 AS
V_POS NUMBER;
BEGIN
V_POS:= INSTR(P_STRING,P_SEPARATOR,1,1);
IF V_POS >0 THEN
RETURN SUBSTR(P_STRING,1,(V_POS - 1));
ELSE
RETURN P_STRING;
END IF;
END GET_STRING_01_FC;
原文：http://www.cnblogs.com/nuaaydh/p/4323286.html