I seem to recall having problems in the past trying to use "Thisform.Whatever" property references in certain places in a SQL call, so, now I tend to do this tecnique to get the form properties into local vars and then using the local vars in the SQL:

lcLookupTable=this.cLookupAlias
lcLookupField=this.cLookupField
lcWhereClause= lcLookupTable + '=' + tcLookup

Select &lcLookupField From &lcLookupTable Where &lcWhereClause Into Array laLookup

Is this the best practice, or can I just directly reference the form properties in a SQL?

Something like this...

Select (thisform.cLookupField) From (thisform.cLookupAlias) where (thisform.cLookupField)=tcLookup Into Array laLookup

That just looks like it won't even work. But it would keep me from creating all those local vars.