How many rows are there in a table?

Counting is one of the easiest SQL statements, so it is also many people's first experience of a PostgreSQL query.

How to do it...

From any interface, the SQL command used to count rows is as follows:

SELECT count(*) FROM table;

This will return a single integer value as the result.

In psql, the command looks like the following:

postgres=# select count(*) from orders;
count
───────

     345
(1 row)

How it works...

PostgreSQL can choose between two techniques available to compute the SQL...