Need help with formula don't want it to skip a line if keyword isn't used

My formula:

=IF(   ISNUMBER(SEARCH("Cash",Sheet2!C2)),   DATEVALUE(Sheet2!A2),"")

I know the main problem is its going by cell# need it to search the column and when key word doesn't match that is doesn't skip a line. Only show when key word Cash is used and not to skip a line.

If buy, sell or any other word is used it skips a line.

I don't want it to skip a line only record the date when Cash is entered.