I want to sum across a range of  fields, but only if the cell contains a number, not a Date.I would love to use something like SUMIF(A2:Z2,!ISDATE(),A2:Z2)But the criteria in SUMIF is incredibly dumb.  Is it possible that  there is a valid solution out there?
SUMIF using NOT ISDATE
google spreadsheets
You can use =SUM(FILTER(A2:Z2,ISERROR(DATEVALUE(A2:Z2)))) where DATEVALUE interprets the content as a date, if it would be auto-converted into a date when entered. Otherwise it throws an error. ISERROR returns True value if its input is an errorFILTER narrows down the data set to those columns or rows where the condition holds. 