How to match a drop down list with a single value from another column

[v_wadhawan]

Sir,
I have 2 tables: ‘DA11’ table with a list of 6 entries under [cat1] and 6 corresponding reference values in col 2 named [da1].
Other table"Pension"has 5 columns. In col named [category ] user has to select one of the items under [cat1]. I did this by valid if = DA11[cat1]. In the 2nd col of table “Pension” the user is automatically shown the value pertaining to his selection in [category]. by using valid if = DA11[da1]. this selects one of the 6 values matching with selected[category].
However, when I use SELECT(da11[da1],([_THISROW].[category] = [category]),TRUE), the user gets all the six values as given under da1 instead of single value . all the six values are shown even when I use SELECT(da11[da], [category]=[_THISROW].[category]) AND OTHER Select uses that I learnt.
I want to know whether use of select does not produce a single value that matches [category]?What other expressions are required to be used in such a scenario.
I am a learner and sorry for putting my query in a complicated manner.
thanks
vk