SQL one to many with inner join

Question

Say I have two tables, table 1 and table 2. Table 1 has a one to many relationship with table 2.

If table 1 is my base table (SELECT something FROM table1) with an inner join to table 2, then what values from table two would be returned when selecting any fields from table 2?

• The first value returned? As with excel's vlookup function?
• The last value on the join?

E.G.

Table1
     Account ID |      email      
         1      |   [email protected]
         2      |   [email protected]
         3      |   [email protected]

Table 2
Subscription ID | Account ID  |       Email       |      Created
    100         |     1       |    [email protected]    |    2014-01-01
    102         |     2       |    [email protected]  |    2014-02-02
    103         |     1       |    [email protected]    |    2014-03-03

So if I ran a query to select the created date of an account based on subscriptions I could just run SELECT min(Created) to get the first one.

But what's the default behavior? If my left table is table 1 joined onto table 2 on account ID and I select created field, which will be returned? 2014-01-01 or 2014-03-03?

Answer 1

You would return both records. When you JOIN tables, you get all the records that meet the criteria of the JOIN and the WHERE clauses and any GROUP BY / HAVING clauses. If you want only one returned, you have to write the code to specify which one you want.