DECLARE V_DATE DATE := SYSDATE; v_var VARCHAR2(20); V_VALID BOOLEAN; BEGIN IF V_VAR IS NULL THEN DBMS_OUTPUT.PUT_LINE('V_VAR IS NULL'); END IF; INSERT INTO T_TEST VALUES (1,'zizhu'); COMMIT; V_VAR := 'HELLO,WORLD'; V_VALID := 'hello,world' LIKE V_VAR;--LIKE 比较字符串是否相等 DBMS_OUTPUT.PUT_LINE(V_VAR); DBMS_OUTPUT.PUT_LINE(TO_CHAR(V_DATE,'YYYY-MM-DD HH:MI:SS')); DBMS_OUTPUT.PUT_LINE('连接' || '两个' || '字符串'); END; / --使用dml语句 DECLARE V_ID BINARY_INTEGER := 23; V_NAME VARCHAR2(30) := 'zizhu8'; BEGIN DELETE FROM T_TEST; INSERT INTO T_TEST VALUES (V_ID,V_NAME); COMMIT; END; / --使用select语句 DECLARE V_COUNT NUMBER(4); V_ID BINARY_INTEGER; V_NAME VARCHAR2(30); BEGIN SELECT COUNT(*) INTO V_COUNT FROM T_TEST; DBMS_OUTPUT.PUT_LINE('T_TEST表中的数据共有:' || V_COUNT || '条'); SELECT ID,NAME INTO V_ID,V_NAME FROM T_TEST; DBMS_OUTPUT.PUT_LINE(V_ID || '对应' || V_NAME); END; / --sql语句的基本使用 DECLARE V_COUNT BINARY_INTEGER;--专门计数使用的类型,效率比较高 V_ID NUMBER(4); V_NAME VARCHAR2(30); BEGIN SELECT COUNT(*) INTO V_COUNT FROM T_TEST; IF V_COUNT = 0 THEN DBMS_OUTPUT.PUT_LINE('T_TEST表中没有数据'); DBMS_OUTPUT.PUT_LINE('向T_TEST表中插入一条数据后....'); INSERT INTO T_TEST SELECT * FROM T_TEST2; END IF; SELECT COUNT(*) INTO V_COUNT FROM T_TEST; DBMS_OUTPUT.PUT_LINE('T_TEST表中共有' || V_COUNT || '条数据'); IF V_COUNT = 1 THEN SELECT ID,NAME INTO V_ID,V_NAME FROM T_TEST; DBMS_OUTPUT.PUT_LINE('T_TEST表中的数据有:' || V_ID || '--' || V_NAME); END IF; V_ID := 1; V_NAME := 'zizhu8'; DBMS_OUTPUT.PUT_LINE('修改这条数据' || V_ID || '--' || V_NAME); UPDATE T_TEST SET ID = V_ID,NAME = V_NAME WHERE ID = (SELECT ID FROM T_TEST WHERE ROWNUM <= 1); SELECT ID,NAME INTO V_ID,V_NAME FROM T_TEST; DBMS_OUTPUT.PUT_LINE('修改T_TEST表中的数据后:' || V_ID || '--' || V_NAME); DELETE FROM T_TEST WHERE ID = (SELECT ID FROM T_TEST WHERE ROWNUM <= 1); DBMS_OUTPUT.PUT_LINE('删除第一条记录后....'); SELECT COUNT(*) INTO V_COUNT FROM T_TEST; DBMS_OUTPUT.PUT_LINE('T_TEST表中共有' || V_COUNT || '条数据'); COMMIT; END; /