When writing a Sumproduct formula, what does ,-- mean?

I know you can use +, what other symbols can you use?

Are there and's or or's symbols?


=SUMPRODUCT(--(Odyssey!$E$2:$E$898=B42),--(Odyssey!$AH$2:$AH$898="N")+
(Odyssey!$AQ$2:$AQ$898 <""))

Sharon

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