Randstad Specialist Testing Interview Questions and Answers

Union combines and removes duplicates, Union all combines without removing duplicates.

• Union is used to combine the result sets of two or more SELECT statements and removes duplicates.

• Union all is used to combine the result sets of two or more SELECT statements without removing duplicates.

• Example: SELECT column1 FROM table1 UNION SELECT column1 FROM table2;

• Example: SELECT column1 FROM table1 UNION ALL SELECT column1 FRO

OLTP is for transaction processing, OLAP is for analytical processing.

• OLTP stands for Online Transaction Processing, used for real-time transaction processing.

• OLAP stands for Online Analytical Processing, used for complex queries and data analysis.

• OLTP databases are normalized, while OLAP databases are denormalized.

• OLTP systems are optimized for read and write operations, while OLAP systems are optimized for read-heavy...read more