mysql全库字段名和注释

SELECT
  COLUMN_NAME 列名,
  COLUMN_TYPE 数据类型,
    DATA_TYPE 字段类型,
  CHARACTER_MAXIMUM_LENGTH 长度,
  IS_NULLABLE 是否为空,
  COLUMN_DEFAULT 默认值,
  COLUMN_COMMENT  备注 
FROM
 INFORMATION_SCHEMA.COLUMNS
where
table_schema ='dev'

SELECT 
  table_name 表名,
  table_comment 表说明 
FROM
  information_schema.TABLES 
WHERE table_schema = '数据库名' 
ORDER BY table_name 

SELECT 
  a.table_name 表名,
  a.table_comment 表说明,
  b.COLUMN_NAME 字段名,
  b.column_comment 字段说明,
  b.column_type 字段类型,
  b.column_key 约束 
FROM
  information_schema.TABLES a 
  LEFT JOIN information_schema.COLUMNS b 
    ON a.table_name = b.TABLE_NAME 
WHERE a.table_schema = '数据库名' 
ORDER BY a.table_name 

select 
COLUMN_NAME 字段名,
column_comment 字段说明,
column_type 字段类型,
column_key 约束 from information_schema.columns 
where table_schema = '库名'
and table_name = '表名' ;