Using SUM, why do I need two queries for one result

[SeanK]

I have the following query (made generic for posting purposes)

gstrSQL = "SELECT SUM(field1) AS est, SUM(field2) AS act,  "
gstrSQL = gstrSQL & "field3, field4, field5, field6, "
gstrSQL = gstrSQL & "field7, field8, field9, field10, field11, field12 "
gstrSQL = gstrSQL & "FROM tablename
gstrSQL = gstrSQL & "WHERE [criteria]
gstrSQL = gstrSQL & "AND [More criteria]
gstrSQL = gstrSQL & "GROUP BY field3, field4, field5, field6, "
gstrSQL = gstrSQL & "field7, field8, field9, field10, field11, field12 "
gstrSQL = gstrSQL & "ORDER BY field5"
rs.Open gstrSQL, cn

When I run this, the numeric fields on which I'm doing a SUM return 0. However, when I do this

gstrSQL = "SELECT SUM(field1) AS est, SUM(field2) AS act
gstrSQL = gstrSQL & "FROM tablename
gstrSQL = gstrSQL & "WHERE [criteria]
gstrSQL = gstrSQL & "AND [More criteria]
rs.Open gstrSQL, cn
gstrSQL = "SELECT field3, field4, field5, field6, "
gstrSQL = gstrSQL & "field7, field8, field9, field10, field11, field12 "
gstrSQL = gstrSQL & "FROM tablename
gstrSQL = gstrSQL & "WHERE [criteria]
gstrSQL = gstrSQL & "AND [More criteria]
gstrSQL = gstrSQL & "ORDER BY field5"
rs.Open gstrSQL, cn

I get my correct totals and all of the data in the fields that I need.

My question is: Why do I need to run two queries to return, what to me, is a single result?