sql - Minimum of dates selection in Access -

i have date clause selection of data. there 2 date fields on form 'oberflache' start , end. want choose minimum of 2 fields. i.e should choose record based on date comes first.here code trying with.

    parameters [forms]![oberflache]![start] datetime, [forms]![oberflache]![end]  datetime; select lau.an, lau.ve, lau.du, lau.sta, lau.a, lau.b, lau.sw, lau.po laufzettel               min(fix(lau.a)) between forms![oberflache]!start , forms![oberflache]!end))          or          min(fix(lau.b)) between forms![oberflache]!start , forms![oberflache]!end; 

where an,ve,du,sta,a,b,sw,po fields table lau. cases

lau.a              lau.b 1.11.2016          5.11.2016 2.11.2016          3.11.2016 20.10.2016         4.11.2016 4.11.2016          28.10.2016 

here when give start , end dates 1.11.2016 , 4.11.2016. want records selected in such way if date of lau.a or lau.b before 1.11.2016 in 3rd record or 4th record must left out , first 2 selected.

with code tried

it gives me error cannot have aggregate function in clause. alternative above?