Mysql Query to return 2 columns as 1
 

I am looking to return 2 columns from 2 different tables as 1 column - is this possible?

eh.

Table1
ID DATA1
10 blahblah
15 blahblah

Table2
ID DATA2
20 blahblah

Say I want to write a query that will return 10,15,20 how would I do this assuming ID is declared the same on both tables?

Please ignore - I just discovered the UNION command.

UNION is very slow as it uses temporary tables. Using a JOIN would be faster.

Any examples of how I can achieve the 1 merged column using a JOIN? i've used a UNION but am concious of performance so would prefer to use a JOIN.

Example
SELECT Data1,Data2
FROM Table1
JOIN Table2 ON Table1.id = Table2.id

I have just noticed you do not have the same ID in both tables???
QUOTE "declared (ID) the same on both tables"

Are the IDs in both tables foreign keys?

What you have written will simply return rows in the format:

data1,data2
data1,data2

Using my example say the column names on either table are different i.e.

Table1
ID1 DATA1
10 blahblah
15 blahblah

Table2
ID2 DATA2
20 blahblah

I want a way of returning the data like this:

ID1
ID1
ID2
ID1

as opposed to this:

ID1,ID2
ID1,ID2

Both ID columns are declared the same eg CHAR(2).

I can get what i want using a UNION but cant find a join to do it. I really dont think your basic join example will provide what i'm looking for needs further honed.

Sorry I miss understood what you were trying to achieve.

Still - any idea whether what i want to achieve can be done with a JOIN? I'm no database expert but just looking at the UNION I have doing the job just now I suspect it isnt the most efficient of solutions.

As far as I know you would need a UNION.