PostgreSQL – UNIONS Clause The PostgreSQL UNION clause/operator is used to combine the results of two or more SELECT statements without returning any duplicate rows. To use UNION, each SELECT must have the same number of columns selected, the same number of column expressions, the same data type, and have them in the same order […]
Category Archives: postgresql
PostgreSQL – NULL Values The PostgreSQL NULL is the term used to represent a missing value. A NULL value in a table is a value in a field that appears to be blank. A field with a NULL value is a field with no value. It is very important to understand that a NULL value […]
PostgreSQL – ALIAS Syntax You can rename a table or a column temporarily by giving another name, which is known as ALIAS. The use of table aliases means to rename a table in a particular PostgreSQL statement. Renaming is a temporary change and the actual table name does not change in the database. The column […]