我在SQL查询中合并Group_Concat函数时遇到问题。我曾尝试使用PHP解决该问题,但我更希望使用SQL使其正确。我的代码在下面,我正在使用最新版本的MYSQL。
SELECT Main.Title, Main.DatePrint, Main.PerformanceDate, Main.Unsure_Sure, Main.Register, Main.notes,
VenueKey.Venue,AuthorKey.Author, CompanyKey.Company, PrintKey.Printer, SourceKey.Source
FROM Main INNER JOIN MainVenue
ON Main.MainID = MainVenue.ID_V
INNER JOIN VenueKey
ON MainVenue.VenueID = VenueKey.ID_V_K
INNER JOIN MainAuthor
ON Main.MainID = MainAuthor.ID_A
INNER JOIN AuthorKey
ON MainAuthor.AuthorID = AuthorKey.ID_A_K
INNER JOIN MainCompany
ON Main.MainID = MainCompany.ID_C
INNER JOIN CompanyKey
ON MainCompany.CompanyID = CompanyKey.ID_C_K
INNER JOIN MainPrinter
ON Main.MainID = MainPrinter.ID_P
INNER JOIN PrintKey
ON MainPrinter.PrinterID = PrintKey.ID_P_K
INNER JOIN MainSource
ON Main.MainID = MainSource.ID_S
INNER JOIN SourceKey
ON MainSource.SourceID = SourceKey.ID_S_K
理想情况下,我想在Author,Venue和Company上使用Group_Concat,但是我一直很难使它工作,而返回一个空值。如果可以解决此问题,请告诉我。
谢谢。
最佳答案
您必须对结果进行分组,以使GROUP_CONCAT可以使用。尝试以下方法:
SELECT
AuthorKey.Author,
GROUP_CONCAT(VenueKey.Venue) AS all_venues,
GROUP_CONCAT(CompanyKey.Company) AS all_companies
...
GROUP BY AuthorKey.Author
以获取作者列表以及例如场所和公司的串联列表。
关于php - SQL帮助〜GROUP_CONCAT,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/9472111/