Postgres and Open Source Experts

In PostgreSQL, a commonly faced error “nextval: reached maximum value” error occurs when a sequence reaches its maximum value and the user is still trying to generate a new value.

To query data from a PostgreSQL table, open SQL Shell, and execute the “SELECT *” command followed by the table name.

In PostgreSQL, the “MINVALUE must be less than MAXVALUE” error can be resolved by increasing the value of the “MAXVLAUE” option and decreasing the value of the “MINVALUE” option or both at the same time.

In PostgreSQL, various in-built functions like pg_sleep(), pg_sleep_until(), and pg_sleep_for() are used to pause or delay the query’s execution for a specific period.

The PostgreSQL users can transform a string or a query result into a comma-separated list using a built-in aggregate function named STRING_AGG().

To restart the PostgreSQL server on CentOS 7, execute the “sudo systemctl restart postgresql” command. It is recommended to periodically restart the PostgreSQL server.

Any view that has at least one updatable column is referred to as an updatable view. An updatable view can have updatable as well as non-updatable columns.

In PostgreSQL, a sequence can be linked with a table’s column to create an auto-incremented column. For this, use the “CREATE SEQUENCE” command along with the “OWNED BY” clause.

“START Value can’t be Greater Than MAXVALUE” error occurs because of two reasons: if the start value is greater than the maximum value or if the user specified an out-of-the-range value.

In PostgreSQL, the “\ds” command, “information_schema”, and “pg_class” catalog are used to get the list of available sequences.