Intermediate SQL Topics-Part 2

SQL Group BY and HAVING

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SQL GROUP BY?

GROUP BY is used in combination with aggregate functions like SUM(), COUNT(), AVG(), MIN(), and MAX() to group rows with the same values in specified columns into summary rows.

🧠 Syntax:

SELECT
  column1,
  column2,
  aggregate_function (column3)
FROM
  table_name
GROUP BY
  column1,
  column2;

The GROUP BY is an optional clause of the SELECT statement. The GROUP BY clause allows you to group rows based on values of one or more columns. It returns one row for each group.

The table on the left side has two columns id and fruit. When you apply the GROUP BY clause to the fruit column, it returns the result set that includes unique values from the fruit column:

SELECT
  fruit
FROM
  sample_table
GROUP BY
  fruit;

In practice, you often use the GROUP BY clause with an aggregate function such as MIN, MAX, AVG, SUM, or COUNT to calculate a measure that provides the information for each group.