SQL dobbeltudtræk i samme SQL-sætning

Use a UNION SELECT

SELECT ....
UNION SELECT ....

If there are duplicate rows then they will not be returned, if you want to see them to use a UNION ALL

SELECT ....
UNION ALL
SELECT ....

I tried UNION but it didnt work for me.

SELECT t_name, t_date, t_text AS text1
FROM mytable
WHERE t_date=='24-12-2007'
UNION
SELECT t_text AS text2
FROM mytable
WHERE t_date=='23-07-2007'

This SQL dont work because there aint the same colums in both 'selects' And I think if I make the same colums it will give me two rows instead of one.

What I want is one row looking like this:
t_name, text1, text2

SELECT users.name, objectives1.t_date, objectives1.t_subject AS this_subject, objectives1.t_methods AS this_objectives, objectives1.t_sociale AS this_sociale, objectives2.t_subject AS prev_subject, objectives2.t_methods AS prev_objectives, objectives2.t_sociale AS prev_sociale
FROM users,  objectives AS objectives1, objectives AS objectives2
WHERE users.id = objectives1.user_id AND users.id = objectives2.user_id AND users.active=True AND objectives1.active=True AND objectives2.active=True
AND objectives1.t_date>=thisTermBeginDate() AND objectives1.t_date<=thisTermEndDate()  AND objectives2.t_date>=prevTermBeginDate() AND objectives2.t_date<=prevTermEndDate()
ORDER BY users.name, objectives1.t_date;

Det her virker :-D