一、sql语句如下：

 SELECT
	a.table_name 表名,
	COLUMN_NAME AS 列名,
	DATA_TYPE AS 数据类型,
	CHARACTER_MAXIMUM_LENGTH AS 长度,
	( CASE WHEN is_nullable = 'NO' THEN '否' ELSE '是' END ) AS 是否可空,
	( CASE WHEN column_key = 'PRI' THEN '是' ELSE '否' END ) AS 是否主键,
	COLUMN_COMMENT AS 说明 
FROM
	INFORMATION_SCHEMA.COLUMNS a 
WHERE
	-- 库名
	table_schema = 'marking-exam-online' 
	-- 表名，不写则是整个库
	AND table_name = 'online_question_paper';