mysql将两条数据的同一字段在一条数据中展示

最新推荐文章于 2022-10-24 11:52:31 发布

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本文介绍了两种不同的SQL查询方法来获取应用程序相关信息，包括应用编号、名称、下载次数等，并通过CASE语句选择不同类型的文件路径。

第一中方法：

SELECT
	m.appnum AS appnum,
	m.appname AS appname,
	m.appdowncoun AS appdowncoun,
	m.length AS length,
	m. LEVEL AS LEVEL,
	m.appinstalledname AS appinstalledname,
	MAX(
		(
			CASE n.type
			WHEN 0 THEN
				n.filepath
			ELSE
				''
			END
		)
	) AS apk,
	MAX(
		(
			CASE n.type
			WHEN 1 THEN
				n.filepath
			ELSE
				''
			END
		)
	) AS pic
FROM
	t_app m,
	t_fileinfo n
WHERE
	(m.appnum = n.appid)
GROUP BY
	m.appnum

第二种方法：

SELECT
	m.appnum AS appnum,
	m.appname AS appname,
	m.appdowncoun AS appdowncoun,
	m.length AS length,
	m. LEVEL AS LEVEL,
	m.appinstalledname AS appinstalledname,
	n.apk AS apk,
	n.pic AS pic
FROM
	t_app m
LEFT JOIN (
	SELECT
		t1.appid,
		t1.filepath AS apk,
		t2.filepath AS pic
	FROM
		t_fileinfo t1,
		t_fileinfo t2
	WHERE
		t1.type = 0
	AND t2.type = 1
	AND t1.appid = t2.appid
) n ON m.appnum = n.appid