先创建表:
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;
插入一些数据。
然后编写控制语句:
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;