What does groupby mean in mysql

Answer: GROUP BY is a SQL statement used in MySQL to group and aggregate data. Detailed description: Group records with the same group by value together. Apply aggregate functions (such as SUM, COUNT, AVG) to each group to produce summary results. Benefits include aggregating data, identifying patterns, eliminating duplicate records, and improving efficiency. The group-by column must appear in the SELECT clause, and aggregate functions can only be applied to numeric or character type columns. Multiple columns can be combined for grouping, and GROUP BY defaults to sorting the grouping by column in ascending order.

GROUP BY: Grouping operation in MySQL

What is GROUP BY?

GROUP BY is a SQL statement in MySQL used to group and aggregate data. It groups records together with the same group by value and applies an aggregate function (such as SUM, COUNT, AVG) to each group, producing summary results.

How to use GROUP BY?

The syntax of the GROUP BY statement is as follows:

<code class="sql">SELECT 聚合函数(列名), 分组依据列
FROM 表名
GROUP BY 分组依据列</code>

Example: Calculate the total salary of each department:

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

Advantages of GROUP BY

• Aggregate data to get the overall trend.
• Identify patterns and relationships in data.
• Eliminate duplicate records and improve query efficiency.

Note

• The group-by column must appear in the SELECT clause (as in the example above).
• Aggregation functions can only be applied to numeric or character type columns.
• You can combine multiple columns for grouping, separated by commas.
• GROUP BY sorts the group by column in ascending order by default.

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