sql help: return any one field from table..

[mfacer]

hey,
I need to check 4 tables in the database, and return a value if found.... there are 4 tables, each one has a "year" column in it. THe user might have only one entry in any one of the 4 tables with say 2004 in the year col.

I need to make an SQL query which queries all 4 tables looking at the year column. If it finds say 2004 in one table, and 2003 in another, I need to return both those values.

I assume it needs to be a nested query or something?

[AstroTeg]

Not enough info on the 4 tables to provide anything really meaningful. Initially, I'd say join (mostlikely left join) the tables together and then query the user. The results returned should be only of those that have year values (may need to add a where clause specifying you want a date that is not null).

Depending on the data, you might have a database design issue here. Instead of 4 tables, maybe this data needs to be in one table. The way you wish to query would imply 1 table. But there's not enough info provided to know otherwise...

[mourisj]

You need to UNION 4 different queries, but they need to have columns of the saaame datatype in the same places:

select u_id, year from table1
union
select u_id, year from table2
union
etc.

JJ Mouris

[mfacer]

thanks for the replies guys...
never heard of a UNION query before! Is that run the same as a standard SELECT?

I need this data in four seperate tables, as the data is different in each... the one column which is the same however is the YEAR column...

cheers - I'll give the UNION method a try 🙂