我在 MySQL 中有三个表,它们连接在一起以显示用户具有的资格。我想创建一个表,其中标题显示类型的完整列表,然后左侧列有用户名,然后列在类型标题下显示到期日期,如下所示:
Type
========
Type ID (PK, Int)
Type (VarChar)
User
========
User_ID (PK, Int)
Name (VarChar)
Qualification
========
Quali_ID (PK, Int)
User_ID (Int)
Type_ID (Int)
DateExpire (Date)
Status (VarChar)
我想创建这样的输出:
Users Type1 Type2 Type3 Type4 .......
User1 Qual Qual Qual .......
User2 Qual Qual .......
User3 Qual .......
User4 Qual Qual Qual Qual .......
并非所有用户都具有所有资格,并且资格状态等于“完全”并且到期日期不是今天的过去。
我在下面的互联网上到处搜索后创建了一些 SQL,但我无法让它包含不存在的类型。
我计划从 PHP 中的 MySQL 查询中获取结果,并展开每一行以使其填充到一个表中。如果有人可以帮助我完成 SQL 以使其显示缺少的 Type 列或提出更好的方法,我将不胜感激。
我的SQL:
SELECT 'User_ID', 'Name', GROUP_CONCAT(Types.Title ORDER BY QualiList.Type_ID) AS QualType
FROM TYPES
INNER JOIN (SELECT DISTINCT Type_ID FROM Qualification) QualiList
ON (QualiList.Type_ID = Types.Type_ID)
UNION ALL
SELECT User.User_ID, User.Name AS Name, GROUP_CONCAT(IFNULL(Qualification.DateExpire,'NA') ORDER BY QualiList.Type_ID) AS QualType
FROM TYPES
INNER JOIN (SELECT DISTINCT Type_ID FROM Qualification) QualiList
ON (QualiList.Type_ID = Types.Type_ID)
LEFT JOIN Qualification ON (Qualification.Type_ID = QualiList.Type_ID)
INNER JOIN User ON (User.User_ID = Qualification.User_ID)
GROUP BY Name
最佳答案
检查答案
SELECT USER,
if(sum(user_id*(1-abs(sign(type_id-1))))>0,DateExpire,'NA') AS TypeADate,
if(sum(user_id*(1-abs(sign(type_id-1))))>0,Status,'NA') AS TypeAStatus,
if(sum(user_id*(1-abs(sign(type_id-2))))>0,DateExpire,'NA') AS TypeBDate,
if(sum(user_id*(1-abs(sign(type_id-2))))>0,Status,'NA') AS TypeBStatus,
if(sum(user_id*(1-abs(sign(type_id-3))))>0,DateExpire,'NA') AS TypeCDate,
if(sum(user_id*(1-abs(sign(type_id-3))))>0,Status,'NA') AS TypeCStatus
FROM (
SELECT U.USER, T.Type, Q.Type_ID, Q.User_ID,Q.DateExpire,Q.Status FROM Qualification Q
LEFT OUTER JOIN TYPE T
ON Q.Type_id = T.ID
LEFT OUTER JOIN USER U
ON Q.User_id = U.ID
GROUP BY T.ID, U.ID
) xxx GROUP BY USER
关于php - MySQL跨表查询3张表,空值显示格子,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/13483789/