LIKE & ILIKE

IF

2.中级语法

CASE WHEN

很复杂

INNER JOIN

OUTER JOIN

CROSS JOIN

笛卡尔积

SELECT *
FROM GameScores
CROSS JOIN Departments

使用多个条件连接-快

UNION&UNION ALL

GET_JSON_OBJECT

3.高级语法

随机取数

EXISTS：量化的谓词