sql - how to find difference between no_of_value and no_of_distinct columns values? -


let number of city entries in station, , let number of distinct city names in station; query value of station. in other words, find difference between total number of city entries in table , number of distinct city entries in table.

input format

the station table described follows: enter image description here

where lat_n northern latitude , long_w western longitude.

you use having filtering resul on aggregated function 

 select city,  count(*), count(distinct city)   station  group city  having count(*) <> count(distinct city)

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