CREATEORREPLACETRIGGER upd_esp_category BEFORE INSERTORUPDATE OF email ON ex_edm_task_detail FOR EACH ROW DECLARE v_category VARCHAR2(64); BEGIN SELECT esp_name INTO v_category FROM ex_edm_esp WHERE mail_suffix=SUBSTR(:new.email,INSTR(:new.email,'@',1,1)+1, LENGTH(:new.email)); if(NVL(LENGTH(v_category),0) =0) THEN v_category :='未知'; ENDIF; :new.category := v_category; END;