mysql数据字典自动生成语句

mysql自动生成数据结构的语句(gym_%需替换成自己的表名前缀)：

select distinct 

a.TABLE_NAME as '表名',

TABLES_.TABLE_COMMENT as '表注释',

a.COLUMN_NAME as '字段名',

a.COLUMN_COMMENT as '字段注释',

a.COLUMN_TYPE as '类型长度',

case when a.IS_NULLABLE='yes' then '√'else '' end as '允许空值',

case when a.COLUMN_DEFAULT='' then '""' else a.COLUMN_DEFAULT end  as '默认值',

a.CHARACTER_SET_NAME as '字符集',

a.COLLATION_NAME as '整理',

a.EXTRA as '自动递增',

case when b.CONSTRAINT_NAME='PRIMARY'  then 'PRIMARY' else '' end  as '主键',

c.CONSTRAINT_NAME  as '外键名',

c.REFERENCED_TABLE_NAME as '关联父表',

c.REFERENCED_COLUMN_NAME as '父表字段',

d. CONSTRAINT_NAME as '索引名称'

from INFORMATION_SCHEMA.COLUMNS as a

left join (select CONSTRAINT_NAME,TABLE_NAME table_name2,COLUMN_NAME col_name2 from INFORMATION_SCHEMA .KEY_COLUMN_USAGE where  CONSTRAINT_NAME='PRIMARY' and table_name like 'gym_%') as b

on a.TABLE_NAME=b.table_name2 and a.COLUMN_NAME=b.col_name2

left join (select CONSTRAINT_NAME,REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAME,TABLE_NAME table_name3,COLUMN_NAME col_name3 from INFORMATION_SCHEMA .KEY_COLUMN_USAGE where REFERENCED_COLUMN_NAME!='' and table_name like 'gym_%') as c

on a.TABLE_NAME=c.table_name3 and a.COLUMN_NAME=c.col_name3

left join (select CONSTRAINT_NAME,REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAME,TABLE_NAME table_name4,COLUMN_NAME col_name4 from INFORMATION_SCHEMA .KEY_COLUMN_USAGE where REFERENCED_COLUMN_NAME is null and CONSTRAINT_NAME!='PRIMARY' and table_name like 'gym_%')
as d 

on a.TABLE_NAME=d.table_name4 and a.COLUMN_NAME=d.col_name4

LEFT JOIN INFORMATION_SCHEMA.TABLES AS TABLES_ ON a.TABLE_NAME=TABLES_.TABLE_NAME

where a.table_name like 'gym_%'

下面这段写得比较规范些，但如果数据库数量比较多的情况下，性能有些差，我几十个数据库，200秒才出来结果：

use `fastadmin-ganentang`;

select distinct 

a.TABLE_NAME as '表名',

TABLES_.TABLE_COMMENT as '表注释',

a.COLUMN_NAME as '字段名',

a.COLUMN_COMMENT as '字段注释',

a.COLUMN_TYPE as '类型长度',

case when a.IS_NULLABLE='yes' then '√'else '' end as '允许空值',

case when a.COLUMN_DEFAULT='' then '""' else a.COLUMN_DEFAULT end  as '默认值',

a.CHARACTER_SET_NAME as '字符集',

a.COLLATION_NAME as '整理',

a.EXTRA as '自动递增',

case when b.CONSTRAINT_NAME='PRIMARY'  then 'PRIMARY' else '' end  as '主键',

c.CONSTRAINT_NAME  as '外键名',

c.REFERENCED_TABLE_NAME as '关联父表',

c.REFERENCED_COLUMN_NAME as '父表字段',

d. CONSTRAINT_NAME as '索引名称'

from INFORMATION_SCHEMA.COLUMNS as a

left join INFORMATION_SCHEMA .KEY_COLUMN_USAGE as b

on  a.TABLE_SCHEMA=b.TABLE_SCHEMA and a.TABLE_NAME=b.TABLE_NAME and a.COLUMN_NAME=b.COLUMN_NAME 

and b.CONSTRAINT_NAME='PRIMARY' 

left join  INFORMATION_SCHEMA.KEY_COLUMN_USAGE as c

on a.TABLE_SCHEMA=c.TABLE_SCHEMA and a.TABLE_NAME=c.TABLE_NAME and a.COLUMN_NAME=c.COLUMN_NAME

and c.REFERENCED_COLUMN_NAME!='' 

left join INFORMATION_SCHEMA .KEY_COLUMN_USAGE as d  

on a.TABLE_SCHEMA=d.TABLE_SCHEMA and  a.TABLE_NAME=d.TABLE_NAME and a.COLUMN_NAME=d.COLUMN_NAME

and d.REFERENCED_COLUMN_NAME is null and d.CONSTRAINT_NAME!='PRIMARY' 

LEFT JOIN  INFORMATION_SCHEMA.TABLES as TABLES_ ON  a.TABLE_SCHEMA=TABLES_.TABLE_SCHEMA and a.TABLE_NAME=TABLES_.TABLE_NAME

where a.TABLE_SCHEMA='fastadmin-ganentang'