MAP_CONTAINS_KEY

Description

Syntax

BOOLEAN map_contains_key(Map<K, V> map, K key)

判断给定 map 中是否包含特定的键 key

Example

mysql> select map_contains_key(map(1, "100", 0.1, 2), "1");
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| map_contains_key(cast(map(cast(1 as DECIMALV3(2, 1)), '100', cast(0.1 as DECIMALV3(2, 1)), cast(2 as TEXT)) as MAP<DECIMALV3(38, 9),VARCHAR(3)>), cast('1' as DECIMALV3(38, 9))) |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                                                                                                                                                                                1 |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.17 sec)

mysql> select map_contains_key(map(1, "100", 0.1, 2), "abc");
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| map_contains_key(cast(map(cast(1 as DECIMALV3(2, 1)), '100', cast(0.1 as DECIMALV3(2, 1)), cast(2 as TEXT)) as MAP<DECIMALV3(38, 9),VARCHAR(3)>), cast('abc' as DECIMALV3(38, 9))) |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                                                                                                                                                                                  0 |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.16 sec)

mysql> select map_contains_key(map(1, "100", 0.1, 2), 0.11);
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| map_contains_key(cast(map(cast(1 as DECIMALV3(2, 1)), '100', cast(0.1 as DECIMALV3(2, 1)), cast(2 as TEXT)) as MAP<DECIMALV3(3, 2),VARCHAR(3)>), cast(0.11 as DECIMALV3(3, 2))) |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                                                                                                                                                                               0 |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.15 sec)

mysql> select map_contains_key(map(null, 1, 2, null), null);
+-----------------------------------------------+
| map_contains_key(map(NULL, 1, 2, NULL), NULL) |
+-----------------------------------------------+
|                                             1 |
+-----------------------------------------------+
1 row in set (0.14 sec)

Keywords

MAP, CONTAINS, KEY, MAP_CONTAINS_KEY