Invalid Argument Type when using Lookup

[ToddM1]

I am trying to  return a TagName using the LookUp function.  TagID in my collection (ProjTagCollection) and TagID in a database (Tags) are my comparisons.  TagID in both sources are INT variables.  

For what it's worth, I may have multiple items in my collection that would need to be looked up, but I would settle for just returning the first TagName to move along the troubleshooting path.

LookUp('[dbo].[Tags]', TagID  = ProjTagCollection.TagID). TagName  (squiggle line under the "=" sign)

P.S. Thanks in advance and many thanks to the people who answer questions for newbies.  

[ToddM1 · Accepted solution]

SOLVED!!!!

DefaultSelectedItems = Filter('[dbo].[Tags]',TagID in ProjTagCollection.TagID)