Google Sheets – How to Sum Only Visible Cells

=SUMIF(D:D,"bob",C:C)

in C column are numbers, in D column are ("bob" or others)

if you wish do not sum all column you can use for example

=SUMIF(D2:D6,"bob",C2:C6)  

Note: Text is case sensitive (Bob is not equal bob)

Please see if my answer to a similar question helps.

Update:

My submission for the Google Docs Script gallery was accepted and you can install it to get the functionality you wish.

The steps:

• Open your spreadsheet
• In the menu go to Tools -> Script gallery...
• Search for Sum by color
• Click Install
• Click the Authorize button if you trust the script and then Close
• go back to the spreadsheet

Now you have three additional functions you can use in your spreadsheet formula:

• sumWhereBackgroundColorIs(color, rangeSpecification)
• sumWhereBackgroundColorIsNot(color, rangeSpecification)
• getBackgroundColor(rangeSpecification)

Please from that the rangeSpecification parameters require quotes (") around them.

For example:

=sumWhereBackgroundColorIs("white", "A1:C4")

sums the values of all cells in the A1:C4 range that have a white background.

Please note that if you don't know the color of a certain cell you can use the provided getBackgroundColor function to find out what the color is. This function is necessary, because some colors are expressed as RGB codes (for example, #00ff00 instead of green).