Mysql 信息架构重复-指定要在“选择”中查询的数据库
我的服务器上有两个名称不同的数据库,但都有一个名为Mysql 信息架构重复-指定要在“选择”中查询的数据库,mysql,information-schema,Mysql,Information Schema,我的服务器上有两个名称不同的数据库,但都有一个名为Clients的表。当我运行一个信息模式查询时,它会返回两个数据库中的列,所以当我只需要一个时,就会得到重复的列 例如: SELECT COLUMN_NAME FROM information_schema.COLUMNS WHERE table_name = 'Clients' 我得到了重复的列,因此First\u Name显示了两次,因为它从两个数据库中的Clients表返回列 我的问题是: 是否有一种方法可以指定在SELECT语句中查询哪
Clients
的表。当我运行一个信息模式查询时,它会返回两个数据库中的列,所以当我只需要一个时,就会得到重复的列
例如:
SELECT COLUMN_NAME FROM information_schema.COLUMNS
WHERE table_name = 'Clients'
我得到了重复的列,因此First\u Name
显示了两次,因为它从两个数据库中的Clients
表返回列
我的问题是:
是否有一种方法可以指定在SELECT语句中查询哪个数据库,以便它只返回我想要的列?例如:
SELECT COLUMN_NAME FROM information_schema.COLUMNS
WHERE db_name = 'DB1' AND table_name = 'Clients'
您正在查找
表\u架构
列
SELECT COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE
TABLE_SCHEMA = 'DB1' AND
TABLE_NAME = 'Clients'
仅供参考,这是我做desc INFORMATION\u SCHEMA.COLUMNS时得到的结果代码>
+--------------------------+---------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------------------+---------------------+------+-----+---------+-------+
| TABLE_CATALOG | varchar(512) | NO | | | |
| TABLE_SCHEMA | varchar(64) | NO | | | |
| TABLE_NAME | varchar(64) | NO | | | |
| COLUMN_NAME | varchar(64) | NO | | | |
| ORDINAL_POSITION | bigint(21) unsigned | NO | | 0 | |
| COLUMN_DEFAULT | longtext | YES | | NULL | |
| IS_NULLABLE | varchar(3) | NO | | | |
| DATA_TYPE | varchar(64) | NO | | | |
| CHARACTER_MAXIMUM_LENGTH | bigint(21) unsigned | YES | | NULL | |
| CHARACTER_OCTET_LENGTH | bigint(21) unsigned | YES | | NULL | |
| NUMERIC_PRECISION | bigint(21) unsigned | YES | | NULL | |
| NUMERIC_SCALE | bigint(21) unsigned | YES | | NULL | |
| DATETIME_PRECISION | bigint(21) unsigned | YES | | NULL | |
| CHARACTER_SET_NAME | varchar(32) | YES | | NULL | |
| COLLATION_NAME | varchar(32) | YES | | NULL | |
| COLUMN_TYPE | longtext | NO | | NULL | |
| COLUMN_KEY | varchar(3) | NO | | | |
| EXTRA | varchar(30) | NO | | | |
| PRIVILEGES | varchar(80) | NO | | | |
| COLUMN_COMMENT | varchar(1024) | NO | | | |
| GENERATION_EXPRESSION | longtext | NO | | NULL | |
+--------------------------+---------------------+------+-----+---------+-------+
您正在查找表\u架构
列
SELECT COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE
TABLE_SCHEMA = 'DB1' AND
TABLE_NAME = 'Clients'
仅供参考,这是我做desc INFORMATION\u SCHEMA.COLUMNS时得到的结果代码>
+--------------------------+---------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------------------+---------------------+------+-----+---------+-------+
| TABLE_CATALOG | varchar(512) | NO | | | |
| TABLE_SCHEMA | varchar(64) | NO | | | |
| TABLE_NAME | varchar(64) | NO | | | |
| COLUMN_NAME | varchar(64) | NO | | | |
| ORDINAL_POSITION | bigint(21) unsigned | NO | | 0 | |
| COLUMN_DEFAULT | longtext | YES | | NULL | |
| IS_NULLABLE | varchar(3) | NO | | | |
| DATA_TYPE | varchar(64) | NO | | | |
| CHARACTER_MAXIMUM_LENGTH | bigint(21) unsigned | YES | | NULL | |
| CHARACTER_OCTET_LENGTH | bigint(21) unsigned | YES | | NULL | |
| NUMERIC_PRECISION | bigint(21) unsigned | YES | | NULL | |
| NUMERIC_SCALE | bigint(21) unsigned | YES | | NULL | |
| DATETIME_PRECISION | bigint(21) unsigned | YES | | NULL | |
| CHARACTER_SET_NAME | varchar(32) | YES | | NULL | |
| COLLATION_NAME | varchar(32) | YES | | NULL | |
| COLUMN_TYPE | longtext | NO | | NULL | |
| COLUMN_KEY | varchar(3) | NO | | | |
| EXTRA | varchar(30) | NO | | | |
| PRIVILEGES | varchar(80) | NO | | | |
| COLUMN_COMMENT | varchar(1024) | NO | | | |
| GENERATION_EXPRESSION | longtext | NO | | NULL | |
+--------------------------+---------------------+------+-----+---------+-------+