Question

SQL: Variables

1. Describe a Table Variable, and why they could be very useful.

2. Discuss why it might be useful to use variables in WHERE clauses. What are some of the places the data representing the variable be derived from?

3. Why might a Common Table Expression be more maintainable than using a SELECT INTO statement?

Answer 1

Answer.

1. In sql table variable is a procedure defined using DECLARE statement. It is useful to assign values to it and can be used later in the sql code.

2. In where class we need to give condition to fetch the data. That condition must need to have values to be compared with other values. So instead of values in the where class we directly use these variables.

3. We can use SET statement other than using SELECT INTO statement.