count case when 与sum case when 的 区别

sum(case when t.ride_num=1 then 1 else 0 end ) as ride_1_times count(case when t.ride_num=1 then 1 else null end ) as ride_1_times  count(case when t.ride_num=1 then 1  end ) as ride_1_times  then=1，两

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