Sum matching columns and rows

The SUMPRODUCT function can handle arrays natively, without requiring control shift enter.

In this case, we are multiplying all values in the named range data by two expressions that filter out values not of interest. The first expression applies a filter based on codes:

(codes=J4)

Since J4 contains "A002", the expression creates an array of TRUE FALSE values like this:

{FALSE,TRUE,FALSE,FALSE,FALSE}

The second expression filters on day:

(days=J5)

Since J4 contains "Wed", the expression creates an array of TRUE FALSE values like this:

{FALSE;FALSE;TRUE;FALSE;FALSE;FALSE;FALSE;TRUE;FALSE;FALSE}

In Excel, TRUE FALSE values are automatically coerced to 1 and 0 values by any math operation, so the multiplication operation coerces the arrays above to ones and zeros, and creates a 2D array with the same dimensions as the original data. The process can be visualized as shown below:

Finally, SUMPRODUCT returns the sum of all elements in the final array, 9.

Count instead of sum

If you want to count matching values instead of summing, you can shorten the formula to:

=SUMPRODUCT((codes=J4)*(days=J5)) // count only

Note this count will include empty cells.

Notes

1. Although the example shows only one matched column, this formula will correctly sum multiple matched columns.
2. If you only need to match columns (not rows) you can use a formula like this.
3. To only match rows, you can use the COUNTIFS function.