What are a pass through and union queries for?

[Paul H]

I have been building access databases for a few years now and have never
built a union or pass through query. What are these strange mythical beasts?
What do they do?

Paul

[Randy Harris]

"Paul H" <no****@nospam.com> wrote in message
news:ll****************@newsfe7-gui.ntli.net...

I have been building access databases for a few years now and have never
built a union or pass through query. What are these strange mythical beasts? What do they do?

Paul

A union query combines the results from two other queries into a single
output. It's not uncommon to need results from more than one logical source
that can't be generated with a single query.

A pass through query is a query that will be "passed through" to a server,
often via ODBC. The query is executed at the server but the results can be
available within Access. This is very common in an environment where Access
is the front end to a RDBMS like SQL Server or Oracle.

HTH,
Randy

[Allen Browne]

RTFM, Paul.

Passthroughs relate only to data stored in a different database, where
Access (JET) should not process the query, but pass it through.

UNIONs combine several SELECT statements into one read-only resultset.

--
Allen Browne - Microsoft MVP. Perth, Western Australia.
Tips for Access users - http://allenbrowne.com/tips.html
Reply to group, rather than allenbrowne at mvps dot org.

"Paul H" <no****@nospam.com> wrote in message
news:ll****************@newsfe7-gui.ntli.net...

I have been building access databases for a few years now and have never
built a union or pass through query. What are these strange mythical
beasts? What do they do?

[Paul H]

I have been building access databases for a few years now and have never
built a union or pass through query. What are these strange mythical beasts?

What do they do?

Paul

A union query combines the results from two other queries into a single
output. It's not uncommon to need results from more than one logical
source
that can't be generated with a single query.

A pass through query is a query that will be "passed through" to a server,
often via ODBC. The query is executed at the server but the results can
be
available within Access. This is very common in an environment where
Access
is the front end to a RDBMS like SQL Server or Oracle.

HTH,
Randy

Heh, funny that, I could have done with a union query on an app that I have
just delivered!

Thanks chaps, very helpful indeed.

Good luck to you.

Paul