SQL JOIN有条件地包含多行

Question

I have 2 tables in a SQLite database that I am accessing it via PHP
This is sample data, it is enough to describe what I want to do but not why.
Lets call these tables: TableA , TableB , and TableC

------------------------
|  Unique_ID  |  Name  |
------------------------
|  1          | Sam    |
------------------------
|  2          | Bob    |
------------------------
|  3          | Jill   |
------------------------

*Assume more rows for other possible foreign keys below
--------------------------------------------
|  Unique_ID  |  Foreign_Key  | Time_Stamp |
--------------------------------------------
|  1          | 1             | 1495298339 |
--------------------------------------------
|  2          | 1             | 1495298350 |
--------------------------------------------
|  3          | 1             | 1495298365 |
--------------------------------------------

What I want in my output would be something line this

------------------------------------
|  Name  | First_Time |  Last_Time |
------------------------------------
|  Sam   | 1495298339 | 1495298365 |
------------------------------------
|  Jill  | 1495298787 | 1495298805 |
------------------------------------

Basically I want to pull the fist and last time stamp into the 1st table, but I am not sure how to do a join line this or if it is even possible, multi-layered select queries with limited results of 1?

I am hoping there is a way to avoid looping through each value in TableA and making two separate queries to get the first (lowest) and last (highest) Time_Stamp in TableB

Answer 1

You can do a join between the first table and a processed version of the second table. The second table is a group by using the Foreign_Key , and the computed values are the minimum and maximum of Time_Stamp . Something like this:

select A.Unique_Id, B.First_Time, B.Last_Time
from TableA as A
join (
    select Foreign_Key, min(Time_Stamp) as First_Time, max(Time_Stamp) as Last_Time
    from Table B
    group by Foreign_Key
) as B
on A.Unique_Id = B.Foreign_Key

Answer 2

SELECT table1.Name, MIN( table2 .Time_Stamp ) AS firstTime, MAX( table2 .Time_Stamp ) AS lastTime
FROM  `table1` 
LEFT OUTER JOIN table2 ON table1.Unique_Id = table2.Unique_Id
GROUP BY table1.Unique_Id

Hope this will help you.

Answer 3

SELECT TableA.name, MIN(TableB.timeid), MAX(TableB.timeid) FROM TableA

INNER JOIN TableB ON TableA.id = TableB.TableA_id 

GROUP BY TableB.TableA_id