Experts in Postgres and Open Source Infrastructure

To find the average of a column we use the AVG() function taking the name of the column as a parameter. The ROUND() function rounds off a specified number up to particular decimal places.

In PostgreSQL, the ordering is done by using the ASC and DESC keywords but we can also customize the sorting order using several ways, such as the CASE keyword, array_position() function, etc.

To change a Primary key in Postgres, remove the existing primary key from the table, and add a new primary key using the “ALTER TABLE ADD PRIMARY KEY” statement.

To concatenate multiple columns in PostgreSQL, the CONCAT() function is used. Moreover, we can also use the concatenation operator “||”.

The NOT LIKE operator looks for the specified character/text/string in the database and returns those records that do not contain that specified string/pattern.

In PostgreSQL, the error “function ntile() Does Not Exist” basically arises when we do not provide any argument to the ntile() function.

To create a tablespace in PostgreSQL, the “CREATE TABLESPACE” statement is used with the “LOCATION” clause. It refers to the location on the disk where all the data for a database is stored.

The REAL data type is a numeric data type used to store the single-precision floating point numbers. It requires fewer storage constraints as compared to the DOUBLE PRECISION data type.

In PostgreSQL, users can get the first, last, and any nth values from each partition using the FIRST_VALUE(), LAST_VALUE(), and NTH_VALUE(), respectively.

First, establish a connection with the postgres database from psql, after that, you can run all the PostgreSQL queries like DDL and DML in psql in similar ways as you run them in pgAdmin.