query_expression_body INTERSECT [ALL | DISTINCT] query_expression_body
    [INTERSECT [ALL | DISTINCT] query_expression_body]
    [...]

query_expression_body:
    See Section 15.2.14, “Set Operations with UNION, INTERSECT, and EXCEPT”

INTERSECT 將多個查詢區塊的結果限制為所有區塊共有的列。範例

mysql> TABLE a;
+------+------+
| m    | n    |
+------+------+
|    1 |    2 |
|    2 |    3 |
|    3 |    4 |
+------+------+
3 rows in set (0.00 sec)

mysql> TABLE b;
+------+------+
| m    | n    |
+------+------+
|    1 |    2 |
|    1 |    3 |
|    3 |    4 |
+------+------+
3 rows in set (0.00 sec)

mysql> TABLE c;
+------+------+
| m    | n    |
+------+------+
|    1 |    3 |
|    1 |    3 |
|    3 |    4 |
+------+------+
3 rows in set (0.00 sec)

mysql> TABLE a INTERSECT TABLE b;
+------+------+
| m    | n    |
+------+------+
|    1 |    2 |
|    3 |    4 |
+------+------+
2 rows in set (0.00 sec)

mysql> TABLE a INTERSECT TABLE c;
+------+------+
| m    | n    |
+------+------+
|    3 |    4 |
+------+------+
1 row in set (0.00 sec)

與 UNION 和 EXCEPT 相同，如果未指定 DISTINCT 或 ALL，則預設為 DISTINCT。

DISTINCT 可以移除交集任一側的重複項，如下所示

mysql> TABLE c INTERSECT DISTINCT TABLE c;
+------+------+
| m    | n    |
+------+------+
|    1 |    3 |
|    3 |    4 |
+------+------+
2 rows in set (0.00 sec)

mysql> TABLE c INTERSECT ALL TABLE c;
+------+------+
| m    | n    |
+------+------+
|    1 |    3 |
|    1 |    3 |
|    3 |    4 |
+------+------+
3 rows in set (0.00 sec)

(TABLE c INTERSECT TABLE c 等同於剛剛顯示的兩個陳述式的第一個。)

與 UNION 相同，運算元的欄位數量必須相同。結果集欄位類型也以 UNION 的方式決定。

INTERSECT 的優先順序高於 UNION 和 EXCEPT，並在其之前計算，因此這裡顯示的兩個陳述式是等效的

TABLE r EXCEPT TABLE s INTERSECT TABLE t;

TABLE r EXCEPT (TABLE s INTERSECT TABLE t);

對於 INTERSECT ALL，左側表格中任何唯一列的最大重複數量為 4294967295。