Join Table To a nested array [PHP/MYSQL]

问题

How to select join multiple tables and get it in a nested array easily?

For Example

Table 1 -School: SchoolID, SchoolName,PrincipalID
Talbe 2 - Principal: PrincipalID,PrincipalName

I want to get a nested array in PHP like

"School": [
            {
                "SchoolID": "7",
                "SchoolName": "New",
                "Principal": {
                      "PrincipalID":"1",
                      "PrincipalName":"James"
                }
            }

The problem is, how to get the nested array use a automatic way instead of specifying each field and add it into a array manually? without even kowning the actual field names, just nesting multiple tables into a nested array.

回答1:

the result of the query can be a single dimension array only. so in other words, you can't create a multidimensional result. You need to do that in the application level, (use your own logic) but there's a function that can help you sometime. It's called GROUP_CONCAT. What it does it is it concatenates its row values into single row and separated by a comma.

• GROUP_CONCAT
• GROP_CONCAT example

来源：https://stackoverflow.com/questions/13437378/join-table-to-a-nested-array-php-mysql