"如何在同一个表中将多行合并为一行但具有不同的列？"

Question

First up, my goal is that some job applicant should be able to upload some files and then submit the application. A HR person in the company should be able to then export the data and the files.

ApplicantID<\/th>	Name<\/th>	Email<\/th>	Column 3<\/th><\/tr><\/thead>
1 <\/td>	Foo<\/td>	Bar<\/td>	Yo<\/td><\/tr>
2 <\/td>	Foo<\/td>	Bar<\/td>	Yo<\/td><\/tr>
3 <\/td>	Foo<\/td>	Bar<\/td>	Yo<\/td><\/tr><\/tbody><\/table> I have another table with the relative paths and the file names of some files the applicant has uploaded. Because of my somewhat clunky frontend design, the file table looks like this (Only the file names are represented): FileID<\/th> Letter<\/th> CV<\/th> Qualifications<\/th><\/tr><\/thead> 1 <\/td> Foo<\/td> NULL<\/td> NULL<\/td><\/tr> 2 <\/td> NULL<\/td> Bar<\/td> NULL<\/td><\/tr> 3 <\/td> NULL<\/td> NULL<\/td> Yo<\/td><\/tr><\/tbody><\/table> Is there any way to get it like this with a query? Column 1<\/th> Column 2<\/th> Column 3<\/th><\/tr><\/thead> Foo<\/td> Bar<\/td> Yo<\/td><\/tr><\/tbody><\/table> I've had the idea of using a third mxn table like this: ApplicantID<\/th> FileID<\/th><\/tr><\/thead> 1 <\/td> 1 <\/td><\/tr> 1 <\/td> 2 <\/td><\/tr> 1 <\/td> 3 <\/td><\/tr><\/tbody><\/table> But here comes the question of how I can get the latest 3 added rows and get individual columns. "

Answer 1

您可以使用JOIN<\/strong>连接三个表并获得所需的列....但请确保在设计表时遵循规范化

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