1.算数运算符 2.连接符 3.比较符 4.IS [NOT] NULL , LIKE , [NOT] IN 5.[NOT] BETWEEN 6.不等于 7.NOT 8.AND 9.OR
例:比较OR与AND的优先级
SQL@itkaifang> SELECT empno,ename,sal FROM emp WHERE ename='SCOTT' OR ename='KING' AND sal>3000; EMPNO ENAME SAL ---------- ---------- ---------- 7788 SCOTT 3000 7839 KING 5000 SQL@itkaifang> SELECT empno,ename,sal FROM emp WHERE sal>3000; EMPNO ENAME SAL ---------- ---------- ---------- 7839 KING 5000 SQL@itkaifang> SELECT empno,ename,sal FROM emp WHERE (ename='SCOTT' OR ename='KING') AND sal>3000; EMPNO ENAME SAL ---------- ---------- ---------- 7839 KING 5000 SQL@itkaifang>