1. information_schema.COLUMNS表记录了所有库中所有表的字段信息 SELECT COLUMN_NAME 字段名称, COLUMN_TYPE 字段类型, COLUMN_DEFAULT 默认值, CHARACTER_MAXIMUM_LENGTH AS 最大长度, ( CASE WHEN is_nullable = 'NO' THEN '否' ELSE '是' END ) AS 是否可空, ( CASE WHEN column_key = 'PRI' THEN '是' ELS…