uniqExact
Calculates the exact number of different argument values.
uniqExact(x[, ...])
Use the uniqExact function if you absolutely need an exact result. Otherwise use the uniq function.
The uniqExact function uses more memory than uniq, because the size of the state has unbounded growth as the number of different values increases.
Arguments
The function takes a variable number of parameters. Parameters can be Tuple, Array, Date, DateTime, String, or numeric types.
Example
In this example we'll use the uniqExact function to count the number of unique type codes (a short identifier for the type of aircraft) in the opensky data set.
Query
SELECT uniqExact(typecode) FROM opensky.opensky
Response
1106
See Also