SQL Clauses

SQL clauses are an essential part of SQL queries and help to filter, sort, and limit the data returned from a database. Some of the most commonly used SQL clauses are:

WHERE

The WHERE clause is used to filter records that meet certain conditions.

Syntax:

SELECT column1, column2, ...
FROM table_name
WHERE condition;
 

GROUP BY

The SQL GROUP BY statement is used to arrange identical data into groups.

• The GROUP BY statement is used with the SQL SELECT statement.
• The GROUP BY statement follows the WHERE clause in a SELECT statement and precedes the ORDER BY clause.
• The GROUP BY statement is often used with aggregation functions (like COUNT(), SUM(), AVG(), etc.).

Syntax

SELECT column1, column2, ...
FROM table_name
WHERE condition
GROUP BY column1, column2, ...
ORDER BY column_name;

HAVING

• The HAVING clause is used to specify a search condition for a group or an aggregate.
• HAVING is used in a GROUP BY clause. If you are not using GROUP BY clause, then you can use the HAVING function like a WHERE clause.

Syntax

SELECT column1, column2, ...
FROM table_name
WHERE condition
GROUP BY column1, column2
HAVING condition
ORDER BY column1, column2;
 

ORDER BY

• The ORDER BY clause sorts the result-set in ascending or descending order.
• It sorts the records in ascending order by default. The DESC keyword is used to sort the records in descending order.

Syntax

SELECT column1, column2, ...
FROM table_name
WHERE condition
ORDER BY column1, column2 ... ASC | DESC;