您如何获取列是否是MySQL中的主键?
要获取列是否为主键,请使用COLUMN_NAME和COLUMN_KEY ='PRI'。这样,整个语法如下:
select column_name, case when column_key= 'PRI' then 'yourMessage1' else ''yourMessage2' end as anyAliasNamefrom information_schema.columns
where table_schema =database()
and `table_name` = yourTableName
order by `table_name`, ordinal_position;
要了解上述语法,让我们创建一个表-
mysql> create table DemoTable1886(
Id int NOT NULL,
FirstName varchar(20),
LastName varchar(20),
Age int,
DateOfBirth datetime,
Education varchar(40),
PRIMARY KEY(Id)
);
这是获取特定列是否为主键的查询-
mysql> select column_name, case when column_key= 'PRI' then 'This is a Primary key Column' else 'This is not a Primary key Column' end as Outputfrom information_schema.columns
where table_schema =database()
and `table_name` = 'DemoTable1886'
order by `table_name`, ordinal_position;
这将产生以下输出-
+-------------+--------------------------------+| COLUMN_NAME | Output |
+-------------+--------------------------------+
| Id | This is a Primary key Column |
| FirstName |This is not a Primary key Column|
| LastName |This is not a Primary key Column|
| Age |This is not a Primary key Column|
| DateOfBirth |This is not a Primary key Column|
| Education |This is not a Primary key Column|
+-------------+--------------------------------+
6 rows in set (0.00 sec)
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