Tutorial Gateway

SQL HAVING Clause

by

The SQL Having Clause is used to restrict the number of rows (or records) returned by the Group By Clause. Where Clause does not allow us to check any conditions against the aggregated data. So, to Check any conditions against the aggregated data we have to use the Having Clause. Please refer Group By Clause before looking into Having Clause.

TIP: To use Having Clause, we have to use Group By Clause because Having clause filters data that we get from Group By Clause. If we haven’t used GROUP BY clause then, Having behaves like a WHERE clause.

NOTE: Where Clause is applied to each row before the Group By Clause is implement but Having Clause is applied after the Group by Statement.

SQL Having Clause Syntax

The Having Clause along with Group By Statement in SQL Server can be written as:

-- SQL Server Having Clause Syntax
SELECT [Column1], [Column2]...[ColumnN],
       Aggregate Function (Expression | Column_Name) 
FROM [Source]
WHERE [Conditions] -- Optional
GROUP BY [Column1], [Column2]...[ColumnN]
HAVING [Conditions] -- This Condition is on Aggregate Function (Expression | Column_Name)
  • Columns: It allows us to choose the number of columns from the tables. It may be One or more.
  • Aggregate Functions: We can use any of the aggregate functions here. SUM, MIN, AVG, MAX and COUNT are the functions we can use.
  • Source: One or more tables present in the Database. SQL JOINs are used to join multiple tables.
  • Conditions: Here we have to provide the filters or conditions. If the condition is TRUE then only SELECT Statement will return the records.
  • Group By: All the Selected Columns which are not part of the Aggregate Functions should place after this Group by clause.
  • Having: We can provide the Filters or Conditions on the Aggregated Data we got from the Group By Clause.

In this article, we will show you, How to write the SQL Having Clause to filter the data after the aggregate function is applied by the group by clause. We are going to use the below-shown data to explain the Having Clause in SQL Server with an example.

SQL HAVING Clause

SQL Having Sum – Using Single Conditions

In this example, we are going to use a single condition in the Having Clause.

-- Sql Server Having Clause Example
SELECT [Occupation]
      ,[Education]
      ,SUM([YearlyIncome]) AS [Total Income]
  FROM [Customer]
  GROUP BY [Occupation], [Education]
  HAVING SUM([YearlyIncome]) > 60000

In the above query, Group By statement will Group the customers by Occupation and Education. Next, Having Clause will check the condition whether the SUM([Yearly Income]) > 60000.

OUTPUT
SQL Having Clause 1

SQL Having Multiple Conditions

In this example we are going to use Multiple Conditions in the Having Clause.

-- Sql Server Having Clause Example
SELECT [Occupation]
      ,[Education]
      ,SUM([YearlyIncome]) AS [Total Income]
  FROM [Customer]
  GROUP BY [Occupation], [Education]
  HAVING SUM([YearlyIncome]) > 60000 AND
         SUM([YearlyIncome]) < 200000

In the above query, Group By statement will Group the customers by Occupation and Education. Next, Having Clause will check the condition whether the SUM([Yearly Income]) > 60000 and less than 200000.

OUTPUT

SQL Having Clause 2

SQL Having Where Clause

We can also use the Where Clause along with the Having Clause.

-- Sql Server Having Clause Example
SELECT [Occupation]
      ,[Education]
      ,SUM([YearlyIncome]) AS [Total Income]
  FROM [Customer]
  WHERE [Education] <> 'Partial High School'
  GROUP BY [Occupation], [Education]
  HAVING SUM([YearlyIncome]) > 60000

Above query will first exact the customer’s data whose Education is Not equal to [Partial High School]. Next, Group By statement will group the customers by Occupation and Education. Last, Having Clause will check the condition whether the SUM([Yearly Income]) > 60000 or not.

OUTPUT

SQL Having Clause 3

Thank You for Visiting Our Blog

Placed Under: SQL