MySQL是目前應用最廣泛的關系型數據庫管理系統之一。MySQL中的子查詢類型使得我們可以更便捷地查詢出數據。下面讓我們來了解一下MySQL中常見的子查詢類型：

1. 標量子查詢
SELECT * FROM tableA WHERE id = (SELECT MAX(id) FROM tableA);
2. 列子查詢
SELECT * FROM tableA WHERE id IN (SELECT id FROM tableB WHERE condition);
3. 行子查詢
SELECT * FROM tableA WHERE (col1, col2) = (SELECT col1, col2 FROM tableB WHERE condition);
4. 子查詢作為表
SELECT * FROM (SELECT col1, col2 FROM tableA WHERE condition) AS t;
5. EXISTS子查詢
SELECT * FROM tableA WHERE EXISTS (SELECT * FROM tableB WHERE condition);
6. NOT EXISTS子查詢
SELECT * FROM tableA WHERE NOT EXISTS (SELECT * FROM tableB WHERE condition);
7. 子查詢作為函數參數
SELECT * FROM tableA WHERE col1 IN (SELECT MAX(col1) FROM tableB WHERE condition);
8. 子查詢使用ANY操作符
SELECT * FROM tableA WHERE col1 >ANY (SELECT col1 FROM tableB WHERE condition);
9. 子查詢使用ALL操作符
SELECT * FROM tableA WHERE col1 >ALL (SELECT col1 FROM tableB WHERE condition);

以上就是MySQL中常見的子查詢類型，應用靈活可以方便我們查找出數據。需要注意的是，子查詢也會對性能產生一定的影響，需要在實際使用中根據數據量和查詢條件進行選擇。