DBA技术分享--MySQL三个关于主键PrimaryKeys的查询

概述

分享作为DBA日常工作中，关于mysql主键的3个常用查询语句，分别如下：

列出 MySQL 数据库中的所有主键 (PK) 及其列

select tab.table_schema as database_schema,
    sta.index_name as pk_name,
    sta.seq_in_index as column_id,
    sta.column_name,
    tab.table_name
from information_schema.tables as tab
inner join information_schema.statistics as sta
        on sta.table_schema = tab.table_schema
        and sta.table_name = tab.table_name
        and sta.index_name = 'primary'
where tab.table_schema = 'your database name'
    and tab.table_type = 'BASE TABLE'
order by tab.table_name,
    column_id;

列说明：

输出示例：

输出结果说明：

列出用户数据库（模式）中没有主键的表

select tab.table_schema as database_name,
       tab.table_name
from information_schema.tables tab
left join information_schema.table_constraints tco
          on tab.table_schema = tco.table_schema
          and tab.table_name = tco.table_name
          and tco.constraint_type = 'PRIMARY KEY'
where tco.constraint_type is null
      and tab.table_schema not in('mysql', 'information_schema', 
                                  'performance_schema', 'sys')
      and tab.table_type = 'BASE TABLE'
--      and tab.table_schema = 'sakila' -- put schema name here
order by tab.table_schema,
         tab.table_name;

注意：如果您需要特定数据库（模式）的信息，请取消注释 table_schema 行并提供您的数据库名称。

列说明：

示例：

输出结果说明：

查询显示了用户数据库（模式）中有多少没有主键的表，以及占总表的百分比

select count(*) as all_tables,
       count(*) - count(tco.constraint_type) as no_pk_tables,
       cast( 100.0*(count(*) - count(tco.constraint_type)) / count(*)
            as decimal(5,2)) as no_pk_percent
from information_schema.tables tab
left join information_schema.table_constraints tco
         on tab.table_schema = tco.table_schema
         and tab.table_name = tco.table_name
         and tco.constraint_type = 'PRIMARY KEY'
where tab.table_type = 'BASE TABLE'
    -- and tab.table_schema = 'database_name' -- put your database name here
      and tab.table_schema not in('mysql', 'information_schema',
                                  'sys', 'performance_schema');

列说明：

示例：