Querying data - SELECT¶
One of the most common tasks, when you work with PostgreSQL, is to query data from tables using the SELECT
statement. The SELECT
is one of the most complex statements in PostgreSQL. It has many clauses that you can combine to form a powerful query.
Because of it's complexity, we divide the the PostgreSQL SELECT
statement tutorial into many shorter tutorials so that you can learn each clause of the SELECT
statement easier. The following are the clauses that appear in the SELECT
statement:
- Select distinct rows by using
DISTINCT
operator. - Filter rows by using
WHERE
clause - Sort rows by using
ORDER BY
clause - Select rows based on various operators such as
BETWEEN
,IN
,LIKE
. - Group rows into groups using
GROUP BY
- Apply conditions for groups using
HAVING
- Join a table to other tables using
INNER JOIN
,LEFT JOIN
,FULL OUTER JOIN
,CROSS JOIN
.
In this tutorial we are using the SELECT
with FROM
clause.
PostgreSQL SELECT
statement syntax¶
Let's start with a basic form of the SELECT
statement that retrieves data from a single table.
SELECT
column1,
column2,
...
FROM
table_name;