Performance of GROUP BY multiple columns

Grouping

More GROUP BY

SQL GROUP BY Basics

It sometimes pays to go back and look at what you think you already know about SQL. Joe Celko gives a quick revision of the GROUP BY and HAVING clauses in SQL that are the bedrock of any sort of analysis of data, and comes up with some nuggets that may not be entirely obvious.

Using the ROLLUP, CUBE, and GROUPING SETS Operators

Greg Larsen discusses the ROLLUP, CUBE and GROUPING SETS operators. These operators are used with the GROUP BY clause and allow you to create subtotals, grand totals and superset of subtotals. Read on to find out more about these additional GROUP BY operators.

Using SQL Server's GROUP BY clause to Summarize your Data

SQL Server’s GROUP BY clause provides you a way to aggregate your SQL Server data and to group data on a single column, multiple columns, or even expressions. Greg Larsen discusses how to use the GROUP by clause to summarize your data.

Aggregrating varchar columns

Concatenate columns grouping on Index column (approach for summing varchar columns by grouping on index)