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> OLAP queries (GROUP BY with aggregate functions like COUNT, SUM, and AVG) do full table scans by definition Isn't it only a full table scan if your query isn

> OLAP queries (GROUP BY with aggregate functions like COUNT, SUM, and AVG) do full table scans by definition Isn't it only a full table scan if your query isn't otherwise filtered? Those functions have to read every row of "something", but that something might not always be a whole table.

sradman 6y ago
Very true, I've edited my comment. Some GROUP BY queries are inexpensive and are fine in an OLTP system if the WHERE clause restriction limits the result set size, most however, are meant to scan a large number of rows.
- Roybot 6y ago
  Thank you - this was insightful.