What Are Group Functions

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What Are Group Functions? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY

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A

Group functions are functions applied to a group of rows. Examples of group functions are:

COUNT(*) - Returns the number of rows in the group.
MIN(exp) - Returns the minimum value of the expression evaluated on each row of the group.
MAX(exp) - Returns the maximum value of the expression evaluated on each row of the group.
AVG(exp) - Returns the average value of the expression evaluated on each row of the group.

2007-05-11, 4728👍, 0💬

How To Apply Filtering Criteria at Group Level
How To Apply Filtering Criteria at Group Level? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY If you want to return only specific groups from the query, you can apply filtering criteria at the group level by using the HAVING clause inside the GROUP BY clause. Note group functions can also... 2007-05-11, 6208👍, 0💬

Can Group Functions Be Mixed with Non-group Selection Fields
Can Group Functions Be Mixed with Non-group Selection Fields? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY If a group function is used in the SELECT clause, all other selection fields must be group level fields. Non-group fields can not be mixed with group fields in the SELECT clause. Th... 2007-05-11, 5375👍, 0💬

How To Sort Output in Descending Order
How To Sort Output in Descending Order? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY If you want to sort a column in descending order, you can specify the DESC keyword in the ORDER BY clause. The following SELECT statement first sorts the "tag" in descending order, then sorts the "counts... 2007-05-11, 5359👍, 0💬

How To Use SELECT Statement to Count the Number of Rows
How To Use SELECT Statement to Count the Number of Rows? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY If you want to count the number of rows, you can use the COUNT(*) function in the SELECT clause. The following tutorial exercise shows you some good example: mysql> SELECT COUNT(*) FROM ... 2007-05-11, 5024👍, 0💬

How To Count Duplicated Values in a Column
How To Count Duplicated Values in a Column? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY If you have a column with duplicated values, and you want to know what are those duplicated values are and how many duplicates are there for each of those values, you can use the GROUP BY ... HAVING ... 2007-05-11, 4993👍, 0💬

Can the Query Output Be Sorted by Multiple Columns
Can the Query Output Be Sorted by Multiple Columns? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY You can specifying multiple columns in the ORDER BY clause as shown in the following example statement, which returns employees' salaries sorted by department and salary value: mysql> SELECT ... 2007-05-11, 4850👍, 0💬

How To Use Group Functions in the SELECT Clause
How To Use Group Functions in the SELECT Clause? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY If group functions are used in the SELECT clause, they will be used on the rows that meet the query selection criteria, the output of group functions will be returned as output of the query. The... 2007-05-11, 4803👍, 0💬

What Are Group Functions
What Are Group Functions? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY Group functions are functions applied to a group of rows. Examples of group functions are: COUNT(*) - Returns the number of rows in the group. MIN(exp) - Returns the minimum value of the expression evaluated on each r... 2007-05-11, 4729👍, 0💬

How To Filter Out Duplications in the Returning Rows
How To Filter Out Duplications in the Returning Rows? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY If there are duplications in the returning rows, and you want to remove the duplications, you can use the keyword DISTINCT in the SELECT clause. The DISTINCT applies to the combination of a... 2007-05-11, 4707👍, 0💬

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