一次检索数据库中所有表的 MAX 个主键值

Question

What I need to do is retrieve the maximum primary key of all tables in my database at once ? That is, my result will be like if I executed the below 2 queries:

SHOW TABLES FROM DATABASE_NAME

SELECT MAX(PRIMARY_KEY) AS maxId FROM TABLE

That is

(first column = TableName , second column = MAX(PK) Of that table)

Pardon if I am doing something wrong. I just do not want to write 80 queries because my database has 80 tables.

Answer 1

If (and only if) your primary keys are AUTO INCREMENT variables you can do this:

SELECT TABLE_NAME, AUTO_INCREMENT
FROM   information_schema.TABLES
WHERE  TABLE_SCHEMA = 'mydb'

Answer 2

Please pay attention to the situation below when choosing the method of retrieving that info and what you are going to do with it:

AUTO_INCREMENT value is stored in memory, so after a server restart, AUTO_INCREMENT value is reset to:

SELECT MAX(ai_col) FROM table_name FOR UPDATE;

This can break things if the database has missing FKs and, for example, you delete some rows that refer to other tables. You would end up by reusing the same id.

Refer to: https://dev.mysql.com/doc/refman/5.7/en/innodb-auto-increment-handling.html#innodb-auto-increment-initialization

Answer 3

SELECT  table_schema, table_name, column_name, data_type, extra
    FROM  `columns`
    WHERE  table_schema = 'mydb'
      AND  extra LIKE '%auto_increment%' 

Optionally JOIN this with Alnitak's Answer.