SELECT * FROM scott.emp;
* 代表所有欄位。
SELECT empno, ename, job FROM scott.emp;
欄位間用英文逗號分隔。
SELECT DISTINCT job FROM scott.emp;
DISTINCT 保留唯一值，對應 ALL (預設) 保留重複。
WHERE job = 'MANAGER' (單引號)。WHERE sal <= 2500。| 運算子 | 名稱 | 範例 |
|---|---|---|
| = | 等於 | job='MANAGER', sal=1100 |
| != / ^= / <> | 不等於 | job!='MANAGER', sal^=1100 |
| < | 小於 | sal<2000, job<'MANAGER' |
| > | 大於 | sal>2000, job>'MANAGER' |
| <= | 小於等於 | sal<=2000, job<='MANAGER' |
| >= | 大於等於 | sal>=2000, job>='MANAGER' |
| IN | 列表包含 | sal IN (2000,1000,3000), job IN ('MANAGER','CLERK') |
| NOT IN | 列表排除 | sal NOT IN (...), job NOT IN (...) |
| BETWEEN ... AND ... | 範圍包含 | sal BETWEEN 2000 AND 3000, job BETWEEN 'MANAGER' AND 'CLERK' |
| NOT BETWEEN | 範圍排除 | sal NOT BETWEEN ... |
| LIKE | 模式比對 | job LIKE 'M%' (M 開頭任意長度), job LIKE 'M__' (M 開頭長度 3) |
| NOT LIKE | 模式排除 | job NOT LIKE 'M%' |
| IS NULL | 是否為空 | sal IS NULL |
| IS NOT NULL | 是否非空 | job IS NOT NULL |
% 代表任意長度字串，_ 代表單一任意字元。LIKE 適用字串欄位。
