W3. SQL Where

Question 1

Q: What is the purpose of the SQL WHERE clause?

Answer 1

A: To filter records and extract only those that meet a specified condition.

Question 2

Q: Write a SQL query to select all customers from Mexico.

Answer 2

SELECT * FROM Customers 
WHERE Country='Mexico';

Question 3

Q: What is the general syntax for using the WHERE clause in SQL?

Answer 3

SELECT column1, column2, …
FROM table_name
WHERE condition;

Question 4

Q: Can the WHERE clause be used in statements other than SELECT?

Answer 4

A: Yes, it can also be used in UPDATE, DELETE, and other statements.

Question 5

Q: How should text and numeric values be formatted in the WHERE clause?

Answer 5

A: Text values should be enclosed in single (or double) quotes, but numeric values should not be enclosed in quotes.

Question 6

Q: Write a query to select a customer with CustomerID equal to 1.

Answer 6

SELECT * FROM Customers 
WHERE CustomerID=1;

Question 7

Q: Provide an example of a SQL query using a comparison operator to filter results.

Answer 7

SELECT * FROM Customers 
WHERE CustomerID > 80;

Question 8

Q: List some operators that can be used in the WHERE clause.

Answer 8

= : Equal
> : Greater than
< : Less than
>= : Greater than or equal
<= : Less than or equal
<> or != : Not equal
BETWEEN : Between a certain range
LIKE : Search for a pattern
IN : Specify multiple possible values for a column