As far as I know, in SQL you cannot 'select a table', you can select some
column(s) from one or many tables at once. The result of such a query is an another table (temporary table) that you retrieve the data from.
Please be more specific about what exactly you want to do (e.g.: "I want to select a column 'z' from table 'tableA' and column 'y' from table 'tableB'") - then I'm sure your question has a pretty simple answer :)
SELECT x.date AS x_date, y.date AS y_date, z.date AS z_date FROM x,y,z;
That produces a result:
+---------+---------+---------+
| x_date | y_date | z_date |
+---------+---------+---------+
| | | |
| | | |
+---------+---------+---------+
Alternatively you can get everything in one column by ussuing a query:
SELECT date FROM x
UNION ALL
SELECT date FROM y
UNION ALL
SELECT date FROM z;
That produces a result:
+-------+
| date |
+-------+
| |
| |
+-------+
In the example above you would get also duplicate values in the single column. If you want to avoid duplicates replace 'UNION ALL' with 'UNION'
I'm still not sure if I undestood what you really want ot achieve, but I still hope that helps
Also take a look at:
http://www.w3schools.com/sql/sql_union.asp
http://www.sql-tutorial.net/SQL-JOIN.asp