GROUP BY

Multi-select

Status

Done

The GROUP BY shows how to group rows into different levels based on columns or expressions.

The purpose of the GROUP BY clause is to combined set of rows into a unique value or expression instead of the duplicated rows that might be retrieve without the application of the GROUP BY clause.

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it is requires to use GROUP BY clause with all non-aggregate columns. In SQL, when using aggregate functions like SUM(), any non-aggregated column in the SELECT statement must be included in the GROUP BY clause.

The syntax:

SELECT 
  column1, 
  column2, 
  column3, 
  aggregate_function(column4)
FROM 
  table_name 
WHERE 
  condition_statement
GROUP BY
 column1, column2, column3 # non-aggregate columns
HAVING
 column1,column2,column3

In the order of execution, group by clause comes after the from clause as shown below:

MySQL evaluates the GROUP BY clause after the FROM and WHERE clauses but before the HAVING, SELECT, DISTINCT, ORDER BY and LIMIT clauses:

In practice, you often use the GROUP BY clause with aggregate functions such as SUM, AVG, MAX, MIN, and COUNT. The aggregate function that appears in the SELECTclause provides the information for each group.

MySQL GROUP BY Examples:

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Example 1: Basic MySQL GROUP BY example

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Example 2: Using MySQL GROUP BY with aggregate functions

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Example 3: MySQL GROUP BY with expression example

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Example 4: Using MySQL GROUP BY with HAVING clause example

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Example 5: Grouping by Multiple Columns

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