oracle pl sql 控制语句_oracle sql developer

CREATE TABLE TB_USER
(
    ID INTEGER PRIMARY KEY,
    USER_NAME VARCHAR2(20) NOT NULL,
    USER_AGE INTEGER NOT NULL
);

CREATE SEQUENCE SEQ_USER
INCREMENT BY 1
START WITH 1
NOMAXVALUE
NOCYCLE
CACHE 10;

CREATE OR REPLACE TRIGGER TR_USER BEFORE INSERT ON TB_USER FOR EACH ROW
BEGIN
    SELECT SEQ_USER.NEXTVAL INTO :NEW.ID FROM DUAL;
END;

DECLARE
V_AGE TB_USER.USER_AGE%TYPE;
V_NAME TB_USER.USER_NAME%TYPE;
BEGIN
  SELECT USER_AGE, USER_NAME INTO V_AGE, V_NAME FROM TB_USER WHERE ID = 1;
  IF V_AGE > 0 THEN
    DBMS_OUTPUT.put_line(V_NAME || '>0');
  END IF;
END;

DECLARE
V_AGE TB_USER.USER_AGE%TYPE;
V_NAME TB_USER.USER_NAME%TYPE;
BEGIN
  SELECT USER_AGE, USER_NAME INTO V_AGE, V_NAME FROM TB_USER WHERE ID = 1;
  IF V_AGE < 0 THEN
    DBMS_OUTPUT.put_line(V_NAME || '<0');
  ELSE
    DBMS_OUTPUT.put_line(V_NAME || '>=0');
  END IF;
END;

DECLARE
V_AGE TB_USER.USER_AGE%TYPE;
V_NAME TB_USER.USER_NAME%TYPE;
BEGIN
  SELECT USER_AGE, USER_NAME INTO V_AGE, V_NAME FROM TB_USER WHERE ID = 1;
  IF V_AGE < 0 THEN
    DBMS_OUTPUT.put_line(V_NAME || '<0');
  ELSIF V_AGE = 0 THEN
    DBMS_OUTPUT.put_line(V_NAME || '=0');
  ELSE
    DBMS_OUTPUT.put_line(V_NAME || '>0');
  END IF;
END;