Author Archives: user

UNION vs JOIN Table of content SQL provides various relational operators to handle data that is spread across multiple tables in a relational database. Out of them, UNION and JOIN queries are fundamentally used to combine data from multiple tables. Even though they are both used for the same purpose, i.e. to combine tables, there […]

SQL – Unique Key Table of content The SQL Unique Key The SQL Unique Key (or, Unique constraint) does not allow duplicate values in a column of a table. It prevents two records from having same values in a column. Unique Key is just an alternative to the Primary Key; as both Unique and Primary […]

SQL – BOOLEAN Table of content A Boolean is a universal data type which stores true or false values. It is used when we define a variable in a column of the table. For instance, a customer wants a list of all the red cars. So, we can find this using the BOOLEAN operator as […]