Mysql查询表字段结构注释的方式

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 = '数据库名'
and table_name = '表名' ; 

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
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
    COLUMN_COMMENT 注释,
    COLUMN_NAME 字段名称,
   data_type   字段类型,
     COLUMN_TYPE 字段类型2,
    (
CASE
    WHEN data_type = 'float' 
    OR data_type = 'double' 
    OR data_type = 'TINYINT' 
    OR data_type = 'SMALLINT' 
    OR data_type = 'MEDIUMINT' 
    OR data_type = 'INT' 
    OR data_type = 'INTEGER' 
    OR data_type = 'decimal' 
    OR data_type = 'bigint' THEN
    '数字' ELSE '文本' 
END 
) AS '数据类型',
    (
    CASE
            WHEN data_type = 'DECIMAL' THEN
            CONCAT( NUMERIC_PRECISION, '/', NUMERIC_SCALE ) 
            WHEN data_type = 'float' 
            OR data_type = 'double' 
            OR data_type = 'TINYINT' 
            OR data_type = 'SMALLINT' 
            OR data_type = 'MEDIUMINT' 
            OR data_type = 'INT' 
            OR data_type = 'INTEGER' 
            OR data_type = 'decimal' 
            OR data_type = 'bigint' THEN
                NUMERIC_PRECISION ELSE CHARACTER_MAXIMUM_LENGTH 
            END 
            ) AS '数据长度/精度' 
        FROM
            INFORMATION_SCHEMA.COLUMNS 
        WHERE
        table_schema = 'db_name'  #修改为数据库名
AND table_name = 'table_name'#修改为表名