Purpose of backticks (`) and apostrophes (') in SQL:

1. Backticks (`):

- Backticks are typically used in SQL to delimit identifiers, such as table names, column names, or aliases, that contain special characters or reserved words. For example:

SELECT `first name`, `last name` FROM `employee` WHERE `department` = 'Sales';        

- Using backticks allows you to use identifiers that might otherwise conflict with SQL syntax or reserved words. It's a way to escape identifiers.

- Not all database systems support the use of backticks. They are commonly used in MySQL and MariaDB, but other systems like PostgreSQL and SQL Server may use double quotes ("") for the same purpose.

2. Apostrophes ('):

- Apostrophes, also known as single quotes, are used in SQL to delimit string literals. String literals represent textual data, such as names, descriptions, or values. For example:

SELECT * FROM `employee` WHERE `department` = 'Sales';        

- String literals must be enclosed within apostrophes in SQL queries.

- Apostrophes are used to specify constant values in SQL, such as text or date values.

In summary, backticks (`) are used to delimit identifiers (e.g., table names, column names) that contain special characters or reserved words, while apostrophes (') are used to delimit string literals (e.g., text values) in SQL queries. They serve different purposes and should not be confused with each other.