Commonly used aggregate functions in mysql include

Commonly used aggregate functions in MySQL are used for summary calculations, including: 1. SUM sum; 2. COUNT count; 3. AVG average; 4. MAX maximum value; 5. MIN minimum value; 6. GROUP_CONCAT connection string.

Commonly used aggregate functions in MySQL

The aggregate functions in MySQL are used to perform summary calculations on data sets. thereby extracting meaningful insights from large amounts of data. The following are the most commonly used aggregate functions:

SUM: Returns the sum of the specified column values.
COUNT: Returns the number of non-null values ​​in the specified column.
AVG: Returns the average value of the specified column value.
MAX: Returns the maximum value in the specified column.
MIN: Returns the minimum value in the specified column.
GROUP_CONCAT: Concatenate the values ​​in the specified column into a string.

Usage

Aggregation functions are usually used with the GROUP BY clause to perform summarization of grouped data. For example:

<code class="sql">SELECT department, SUM(salary)
FROM employees
GROUP BY department;</code>

This will sum employee salaries by department and return the total salary for each department.

Other usage

Aggregation functions can also be used for statistical calculations, for example:

• Use COUNT(*) to count table rows number.
• Use AVG(DISTINCT column) to calculate the average of unique values ​​in the specified column.
• Use MAX(CASE WHEN condition THEN value END) to find the maximum value that meets a specific condition.

Choosing an appropriate aggregation function

Choosing an appropriate aggregation function depends on the type of aggregation that needs to be performed. Here are some guidelines:

• For sum calculations, use SUM.
• For counting, use COUNT.
• For average calculation, use AVG.
• For maximum or minimum comparisons, use MAX or MIN.
• For connection strings, use GROUP_CONCAT.

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