关于mysql使用sql语句查询数据库所有表注释已经表字段注释

/* 查询数据库 ‘mammothcode’ 所有表注释 */
SELECT TABLE_NAME,TABLE_COMMENT FROM information_schema.TABLES WHERE table_schema='mammothcode';

/* 查询数据库 ‘mammothcode’ 下表 ‘t_adminuser’ 所有字段注释 */
SELECT COLUMN_NAME,column_comment FROM INFORMATION_SCHEMA.Columns WHERE table_name='t_adminuser' AND table_schema='mammothcode'

SELECT t.TABLE_NAME,t.TABLE_COMMENT,c.COLUMN_NAME,c.COLUMN_TYPE,c.COLUMN_COMMENT 
FROM information_schema.TABLES t,INFORMATION_SCHEMA.Columns c 
WHERE c.TABLE_NAME=t.TABLE_NAME AND t.`TABLE_SCHEMA`='mammothcode'

SELECT  tab.TABLE_NAME,tab.TABLE_COMMENT FROM  information_schema.COLUMNS col 
LEFT JOIN  information_schema.`TABLES` tab on col.TABLE_NAME = tab.TABLE_NAME and col.table_schema = tab.table_schema
WHERE  col.COLUMN_NAME='userid' and col.table_schema = 'mammothcode'