Author Archives: user

SQL – UNION vs UNION ALL Table of content UNION and UNION ALL operators are just the SQL implementation of algebraic set operators. Both of them are used to retrieve the rows from multiple tables and return them as one single table. The difference between these two operators is that UNION only returns distinct rows […]

SQL – BETWEEN Operator Table of content The SQL BETWEEN Operator The BETWEEN operator is a logical operator in SQL, that is used to retrieve the data within a specified range. The retrieved values can be integers, characters, or dates. You can use the BETWEEN operator to replace a combination of “greater than equal AND […]

SQL – NOT NULL Constraint Table of content In a table, columns can typically accept NULL values by default. However, if you want to ensure that a particular column does not contain NULL values, you need to add the NOT NULL constraint/condition on that column. The SQL NOT NULL Constraint The NOT NULL constraint in […]