Hansa Cequity Plsql Developer Interview Questions and Answers

Join operator is used to combine rows from two or more tables based on a related column between them.

• Join operator is used in SQL to retrieve data from multiple tables.

• It combines rows from two or more tables based on a related column between them.

• Types of join operators include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN.

• Join operator can be used with WHERE clause to filter the results.

• Example: SELECT * FRO...read more

Indexes should be created on columns that are frequently used in WHERE, JOIN, and ORDER BY clauses.

• Indexes should be created on columns with high selectivity

• Indexes should not be created on columns with low cardinality

• Indexes should not be created on columns with frequent updates

• Composite indexes can be created on multiple columns

• Indexes can be created on virtual columns

row_number() function assigns a unique number to each row within a result set.

• It is a window function in SQL

• It is used to generate a unique sequential number for each row in a result set

• It is often used for pagination and ranking purposes

• It can be used with ORDER BY clause to specify the order of the rows