MySQL 如何识别所有表中是否存在特定列

要识别列名称，请在MySQL中使用INFORMATION_SCHEMA.COLUMNS。以下是语法 –

select table_name,column_name
from INFORMATION_SCHEMA.COLUMNS
where table_schema = SCHEMA()
andcolumn_name='anyColumnName';

让我们实现上述查询，以便在所有表中识别具有其存在的列。在这里，我们正在查找列EmployeeAge的存在性 –

mysql> select table_name,column_name
   FROM INFORMATION_SCHEMA.COLUMNS
   WHERE table_schema = SCHEMA()
   AND column_name='EmployeeAge';

这将生成以下输出，显示具有特定列“EmployeeAge”的表 –

+---------------+-------------+
| TABLE_NAME    | COLUMN_NAME |
+---------------+-------------+
| demotable1153 | EmployeeAge |
| demotable1297 | EmployeeAge |
| demotable1303 | EmployeeAge |
| demotable1328 | EmployeeAge |
| demotable1378 | EmployeeAge |
| demotable1530 | EmployeeAge |
| demotable1559 | EmployeeAge |
| demotable1586 | EmployeeAge |
| demotable1798 | EmployeeAge |
| demotable1901 | EmployeeAge |
| demotable511  | EmployeeAge |
| demotable912  | EmployeeAge |
+---------------+-------------+
12 rows in set (0.00 sec)

为了证明这一点，让我们检查以上任何一个表的描述 –

mysql> desc demotable1153;

这将生成以下输出，显示在demotable1153中存在EmployeeAge列 –

+--------------+-------------+------+-----+---------+----------------+
| Field        | Type        | Null | Key | Default | Extra          |
+--------------+-------------+------+-----+---------+----------------+
| EmployeeId   | int(11)     | NO   | PRI | NULL    | auto_increment |
| EmployeeName | varchar(40) | YES  | MUL | NULL    |                |
| EmployeeAge  | int(11)     | YES  |     | NULL    |                |
+--------------+-------------+------+-----+---------+----------------+
3 rows in set (0.00 sec)

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