Can we use function in GROUP BY?

Question

The GROUP BY statement groups rows that have the same values into summary rows, like "find the number of customers in each country". The GROUP BY statement is often used with aggregate functions ( COUNT() , MAX() , MIN() , SUM() , AVG() ) to group the result-set by one or more columns.

Can we use expression in GROUP BY?

This is allowed. This rule is followed by the fact that no matter how complex a compound expression is, if it occurs in a GROUP BY clause, it can be included in its entirety only in the SELECT clause.

Can we use window function with GROUP BY?

The reason why window functions are not allowed in GROUP BY is the order of operations in SQL. The clauses of a SQL query are processed in a different order than they are written in the query.

Can GROUP BY have aggregate function?

What Is Group By in SQL? The Group By statement is used to group together any rows of a column with the same value stored in them, based on a function specified in the statement. Generally, these functions are one of the aggregate functions such as MAX() and SUM().

How does the GROUP BY function work?

The GROUP BY clause instructs the DBMS to group the data and then perform the aggregate (function) on each group rather than on the entire result set. Aside from the aggregate calculation statements, every column in your SELECT statement must be present in the GROUP BY clause.

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