Hi, your second method is probably a little too confusing (advanced) for
me to understand.
I used your first method which works fine.. thanks for the crazy stuff,
somtimes you need two crazy people to come up with a solution ;)
[EMAIL PROTECTED] wrote:
Hi Sebastian;
There is always crazy things somewhere.
I'll give you two methods for that :
mysql> select id,'news' as selected, type from news
-> union select id,'faq' as selected, type from faq
-> union select id,'forum' as selected, type from forum;
+------+----------+-------+
| id | selected | type |
+------+----------+-------+
| 1 | news | news |
| 2 | faq | faq |
| 3 | forum | forum |
+------+----------+-------+
3 rows in set (0.00 sec)
FIRST CRAZY METHOD :
*************************
mysql> set @cat='news';
Query OK, 0 rows affected (0.00 sec)
mysql> select * from (
-> select id,'news' as selected, type from news
-> union select id,'faq' as selected, type from faq
-> union select id,'forum' as selected, type from forum
-> ) Temp
-> where [EMAIL PROTECTED];
+------+----------+------+
| id | selected | type |
+------+----------+------+
| 1 | news | news |
+------+----------+------+
1 row in set (0.00 sec)
SECOND CRAZY METHOD (I prefer):
*************************
set @cat := 'news';
set @sql:=concat('select id,','''',@cat,'''',' as selected from ',@cat);
select @sql;
prepare stmt from @sql ;
execute stmt;
+------+----------+
| id | selected |
+------+----------+
| 1 | news |
+------+----------+
1 row in set (0.00 sec)
deallocate prepare stmt;
********* another click with ?cat=faq
set @cat := 'faq';
set @sql:=concat('select id,','''',@cat,'''',' as selected from ',@cat);
select @sql;
prepare stmt from @sql ;
execute stmt;
mysql> execute stmt;
+------+----------+
| id | selected |
+------+----------+
| 2 | faq |
+------+----------+
1 row in set (0.00 sec)
deallocate prepare stmt;
OTHER CRAZY METHODS - coming emails :o)
--------------------
A+
Mathias
Selon Sebastian <[EMAIL PROTECTED]>:
Michael Stassen wrote:
Sebastian wrote:
i have a query with 3 union selects:
SELECT id, 'news' AS type, .... FROM news
UNION
SELECT id, 'faq' AS type, .... FROM faq
UNION
SELECT id, 'forum' AS type, .... FROM forum
which works just fine and selects everything from all 3 tables.. but
say i want to make a condition to only select from either 'faq' ,
'news' or 'forum' how can i do this?
example, if a user visits a link suck as: page.php?cat=faq it will
only select from 'faq' .. is this possible to do right in the query?
when there is no ?cat= then all three selects run.
makes sense? i am stuck on this for a few days already.
thanks.
Why don't you do this in your app? If cat is set, issue the
appropriate single-table query, otherwise issue the union. Surely
that would be simpler than trying to build one multi-purpose query.
Michael
I was hoping i could do some crazy thing like WHERE type = 'faq' so i
can do it all from one block of code.
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