Counting Text Fields in Column

[#1]

In my Excel source on Incidents, I have a column called "Harm". I want a bar chart created when  Harm = yes since there are yes and no values in that column. I want to get the count of 'yes' values only. Please let me know how the expression should be. Thanks

[#2]

Sorry I want to get the count when Harm = yes.

[JonnyPoole · Accepted solution]

Sum ( if( Harm='yes', 1,0))

or

substringcount( concat( Harm,',') , 'yes')

[#4]

Thanks Jonathan It worked