Oracle實例，具體運用
Oracle關鍵字的使用
使用insert 添加數據: INSERT INTO 表名 VALUES (加入對應的數); COMMIT;
INSERT INTO p_emp
VALUES(‘TOM2‘, ‘CLERK‘, 7902, SYSDATE, 1000, NULL, 30);
COMMIT;
試用DELETE刪除一條數據: DELETE 表名 WHERE 條件; COMMIT;
DELETE p_emp e WHERE e.empno=1;
COMMIT;
使用UPDATE修改數據: UPDATE 表名 SET 修改內容 WHERE 條件; COMMIT;
UPDATE p_emp e SET e.ename=‘TOM3‘ WHERE e.empno=2;
COMMIT;
IN 關鍵字 ，查詢在符合IN條件的數據。例：查詢工資為800,3000,5000的員工信息
SELECT * FROM p_emp e WHERE e.sal IN (800, 3000, 5000);
LIKE關鍵字，模糊查詢，%表示任意個字符, _表示單個字符。例：查詢以T開頭的所以員工的信息
SELECT * FROM p_emp e WHERE e.ename LIKE ‘T%‘
ORDER BY,按列名或索引排序
SELECT * FROM p_emp e ORDER BY e.job DESC, e.sal DESC
SELECT * FROM p_emp e ORDER BY 3, 6
GROUP BY 按某幾列分組
SELECT e.job FROM p_emp e GROUP BY e.job HAVING COUNT(*) > 2
使用SUM，AVG，MOD，COUNT函數
SELECT p.toma,p.ptype,SUM(p.lastcou) FROM product p GROUP BY ROLLUP (p.toma,p.type)
CASE WHEN THEN / DECODE的使用
CASE * WHEN 條件THEN 顯示的內容
DECODE(*,’條件’,’顯示的內容’)
SELECT T.ENAME,
CASE T.SEX WHEN 1 THEN ‘男‘ WHEN 0 THEN ‘女‘ ELSE ‘kk‘ END
FROM P_EMP T
SELECT T.ENAME 姓名,
CASE WHEN T.SEX = 1 THEN ‘男‘ WHEN T.SEX = 0 THEN ‘女‘ ELSE ‘kk‘
END 性別
FROM P_EMP T
DISTINCT去除重復
SELECT DISTINCT t.job FROM p_emp t
BETWEEN a AND b 在a和b之間
select * FROM p_emp t WHERE t.sal BETWEEN 2000 AND 3000
Oracle實例，具體運用