如何在MySQL中选择列数最多的表？

你可以使用INFORMATION_SCHEMA.COLUMNS来获取列数最多的表。

语法如下—

SELECT TABLE_NAME, COUNT(*) AS anyAliasName
FROM INFORMATION_SCHEMA.COLUMNS
GROUP BY TABLE_NAME
ORDER BY yourAliasName DESC
LIMIT 1;

以下是选择具有最多列数的表的查询。我们得到这个结果是因为我们将计数设置为DESC并使用GROUP BY TABLE_NAME –

mysql> SELECT TABLE_NAME, COUNT(*) as TOTAL_COUNT
FROM INFORMATION_SCHEMA.COLUMNS
GROUP BY TABLE_NAME
ORDER BY TOTAL_COUNT DESC
LIMIT 1;

这将产生以下输出 –

+-----------------------------------+-------------+
| TABLE_NAME                         | TOTAL_COUNT |
+-----------------------------------+-------------+
| table_lock_waits_summary_by_table | 68          |
+-----------------------------------+-------------+
1 row in set (0.12 sec)

你还可以使用以下查询获取最少的列数。我们得到这个结果是因为我们将计数设置为ASC并使用 GROUP BY TABLE_NAME –

mysql> SELECT TABLE_NAME, COUNT(*) as TOTAL_COUNT
FROM INFORMATION_SCHEMA.COLUMNS
GROUP BY TABLE_NAME
ORDER BY TOTAL_COUNT ASC
LIMIT 1;

这将产生以下输出 –

+-----------------------+-------------+
| TABLE_NAME            | TOTAL_COUNT |
+-----------------------+-------------+
| removenullrecordsdemo | 1           | 
+-----------------------+-------------+
1 row in set (0.14 sec)

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