G
Guest
I'm using a UNION query to join survey results for different types of
questions (rating questions are in one table, text answers are in a different
table). I ran into a situation where using UNION ALL to get data from the two
tables was only bringing back data from the first table in the query. But,
when I changed it to UNION (*not* UNION ALL), all data were brought back.
I thought that UNION ALL is needed to ensure all data are brought back. Why
would using UNION ALL in my case actually return *less* data?
I can post my query if needs be, but I was wondering if this was more of a
general phenomenon and not necessarily limited to my query.
Thanks
rachael
questions (rating questions are in one table, text answers are in a different
table). I ran into a situation where using UNION ALL to get data from the two
tables was only bringing back data from the first table in the query. But,
when I changed it to UNION (*not* UNION ALL), all data were brought back.
I thought that UNION ALL is needed to ensure all data are brought back. Why
would using UNION ALL in my case actually return *less* data?
I can post my query if needs be, but I was wondering if this was more of a
general phenomenon and not necessarily limited to my query.
Thanks
rachael