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6.1.18 group

Usage:

   group [-[no]parallel] <key> [<key> ...] [<aggcol> ...]

Calculates aggregate functions on groups of rows. This does the same job as a SELECT ... GROUP BY statement with aggregate functions in ADQL/SQL.

The functionality is identical to that of the tgroup command, and the meaning and syntax of the <key> and <aggcol> words are identical too, except that the <aggcol> delimiter character is an at sign ("@") rather than a semicolon (";"), so a group entry count can be added for instance using an <aggcol> like "null@count". The <aggcol> arguments are distinguished by the fact that they contain at least one delimiter ("@"). See the tgroup documentation for a full explanation of the syntax and functionality.

The syntax here is rather cramped, so in many cases it will be more comfortable to use tgroup instead, but this filter is provided for cases where that may be more convenient.


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STILTS - Starlink Tables Infrastructure Library Tool Set
Starlink User Note256
STILTS web page: http://www.starlink.ac.uk/stilts/
Author email: m.b.taylor@bristol.ac.uk
Mailing list: topcat-user@jiscmail.ac.uk