EXAM PREP

Question 1

How do you query data from multiple tables in SQL?

Answer 1

You can use a JOIN statement to combine data from multiple tables based on a related column between them, such as using INNER JOIN, LEFT JOIN, etc.

Question 2

What is a CASE statement in SQL?

Answer 2

The CASE statement is used to create conditional logic within a query, allowing you to return different values based on conditions (similar to an IF-ELSE in programming).

Question 3

How can you remove a substring from a string in SQL?

Answer 3

You can use the REPLACE or REGEXP_REPLACE function to remove specific substrings.

Question 4

How do you delete records in a SQL table?

Answer 4

Use the DELETE FROM statement followed by a WHERE clause to specify which rows to remove. Without a WHERE clause, all rows will be deleted.

Question 5

How do you update records in a SQL table?

Answer 5

Use the UPDATE statement along with the SET clause to modify values. You must include a WHERE clause to specify which rows to update.

Question 6

What is the purpose of the GROUP BY clause in SQL?

Answer 6

The GROUP BY clause is used to group rows that have the same values in specified columns and allow aggregate functions (like SUM(), AVG()) to operate on those groups.

Question 7

How can you format numbers with commas and decimal places in SQL?

Answer 7

You can use the FORMAT function to format numbers with commas and a specified number of decimal places. For example, FORMAT(price, 2) formats a price with two decimal places.

Question 8

The SQL keyword INSERT …

Answer 8

adds rows to tables.