What are the functions of the replace function in SQL?

The REPLACE function in SQL is primarily used to replace a specific substring within a string. It serves several purposes.

1. Replace the specified substring in a string: Can be used to replace certain or multiple specified substrings in a string with a new string.
2. Delete specified substrings: Remove one or more specific substrings from a string.
3. Insert new substring: It is possible to insert a new substring at one or more specified positions within the string.
4. Convert letter case: Convert the letter characters in the string to uppercase or lowercase.
5. Regular expression replacement: You can use regular expressions to replace matching items in a string.

In summary, the REPLACE function can be used to perform various replacement operations within a string, making it more flexible and convenient to handle strings.