The following Set of assignment statements at the back of the column name is dynamically generated, the column is made up of fid and CONVERT (VARCHAR (2), b. d, 103) dynamically generated, this statement how to write, please? Thank you very much!

The update ta set FID=fTb + CONVERT (VARCHAR (2), b. d, 103) from ta a, TB b
Where a.f a1=b. a1