RESULT_SCAN

通过查询 ID 检索先前查询的缓存结果。

另请参阅：system.query_cache

语法

RESULT_SCAN('<query_id>' | LAST_QUERY_ID())

示例

以下示例展示了如何启用查询结果缓存，并运行一个其结果将被缓存的查询：

# Enable the query result cache feature
mysql> SET enable_query_result_cache = 1;
Query OK, 0 rows affected (0.01 sec)

# Cache all queries regardless of how fast they execute
mysql> SET query_result_cache_min_execute_secs = 0;
Query OK, 0 rows affected (0.01 sec)

# Execute a query and cache its result
mysql> SELECT * FROM t1 ORDER BY a;
+------+
| a    |
+------+
|    1 |
|    2 |
|    3 |
+------+
3 rows in set (0.02 sec)
Read 0 rows, 0.00 B in 0.006 sec., 0 rows/sec., 0.00 B/sec.

结果被缓存后，你可以使用 RESULT_SCAN 检索该结果，而无需重新运行查询：

# Retrieve the cached result of the previous query using its query ID
mysql> SELECT * FROM RESULT_SCAN(LAST_QUERY_ID()) ORDER BY a;
+------+
| a    |
+------+
|    1 |
|    2 |
|    3 |
+------+
3 rows in set (0.02 sec)
Read 3 rows, 13.00 B in 0.006 sec., 464.06 rows/sec., 1.96 KiB/sec.