Optimized count distinct...

markp201 — Wed, 21 Dec 2016 16:07:06 GMT

I read about a technique to identify distinct field values. Assuming SourceTable is loaded with carmodel field

DistinctCarmodel:

LOAD DISTINCT

carmodel,

Autonumber(carmodel) AS %Distinct_carmodel

RESIDENT

SourceTable

With simple or complex set analysis, we can use

count(%Distinct_carmodel)

max(%Distinct_camodel)

I tweaked this idea a bit with the following

DistinctCarmodel:

LOAD DISTINCT

carmodel,

Autonumber(carmodel,'distinctcarmodel') AS %Distinct_carmodel

RESIDENT

TempSourceTable;

SourceTable:

LOAD

carmodel,

Autonumber(carmodel,'distinctcarmodel') AS %Distinct_carmodel

RESIDENT

TempSourceTable;

DROP TABLE DistinctCarmodel;

The one difference is we would have to use

max(%Distinct_camodel)

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