Author Archives: user

Left Join vs Right Join Table of content The main difference between the Left Join and Right Join can be observed in the way tables are joined. They are both types of Outer Joins; that is, they retain unmatched rows in one table and discard the unmatched rows of another. Left Join preserves the unmatched […]

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 […]

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 […]