MySQL选择具有多个特定列的所有表 [英] MySql select all tables with multiple specific columns

问题描述

我想获取所有具有3个特定列的表名.

I want to get all table names which has 3 specific columns.

我想从信息架构中获取所有表名，其中包含columnA AND columnB AND .

What I want is from information schema I want to get all table names which contains columnA AND columnB AND columnC.

当前我正在使用类似的查询

Currently I am using a query like

SELECT DISTINCT TABLE_NAME 
  FROM INFORMATION_SCHEMA.COLUMNS
    WHERE COLUMN_NAME='columnA'
        AND TABLE_SCHEMA='mysampledatabase';

如何扩展以上查询，并选择包含列名称为columnA和columnB的表?

How can I extend the above query and select tables which contains column names columnA and columnB ?

我遇到了

I came across this answer and other similar answers. They have answered following:

SELECT DISTINCT TABLE_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE COLUMN_NAME IN ('columnA','ColumnB') AND TABLE_SCHEMA='YourDatabase';

SELECT DISTINCT TABLE_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE COLUMN_NAME IN ('columnA','ColumnB') AND TABLE_SCHEMA='YourDatabase';

但是，他们选择具有3列之一的任何表.我相信这是因为WHERE COLUMN_NAME IN ('columnA','ColumnB','ColumnC')我相信等同于COLUMN_NAME = 'columnA' OR COLUMN_NAME = 'columnB' OR COLUMN_NAME = 'columnC'

However what they select any table which has either of the 3 columns. I believe that is because of WHERE COLUMN_NAME IN ('columnA','ColumnB','ColumnC') which , i believe, is equivalent to COLUMN_NAME = 'columnA' OR COLUMN_NAME = 'columnB' OR COLUMN_NAME = 'columnC'

我试图用WHERE COLUMN_NAME='columnA' AND COLUMN_NAME='columnB' AND COLUMN_NAME='columnC'替换WHERE子句，该子句显然不会返回任何结果，因为COLUMN_NAME一次只能是1个值！

I have tried to replace the WHERE clause with WHERE COLUMN_NAME='columnA' AND COLUMN_NAME='columnB' AND COLUMN_NAME='columnC' which obviously doesn't return any results because COLUMN_NAME can only be 1 value at a time!

推荐答案

以下查询可能对您有帮助:

Here is query which might help you:

SELECT`TABLE_SCHEMA`, `table_name`,c1.`column_name`,c2.`column_name`,c3.`column_name` FROM `COLUMNS` C1
INNER JOIN `COLUMNS` C2 USING(`TABLE_SCHEMA`, `TABLE_NAME`)
INNER JOIN `COLUMNS` C3 USING(`TABLE_SCHEMA`, `TABLE_NAME`)
WHERE c1.`column_name` = 'col1'
AND c2.`column_name` = 'col2'
AND c3.`column_name` = 'col3';

但是，您需要为每个要查找的列添加|删除额外的JOIN.

But you will need to add|remove extra JOIN for each column you looking for.

现在，我认为它有点沉重且难以理解，这是另一种选择:

Now i think it's kind of heavy and hard to understand, here is another option:

SELECT table_schema, table_name, count(*) AS `TablesCount` FROM `COLUMNS`
WHERE `column_name` IN ('col1','col1','col1')
GROUP BY table_schema, table_name
HAVING `TablesCount` = 3

TablesCount应该等于您要查找的列数.如果是这样，那么您的表将包含所有必填列

TablesCount should be equal number of columns you looking for. If it's so, then your table have all required columns

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