Charindex SQL

The `CHARINDEX` function is a powerful tool for string manipulation in SQL. It allows you to search for a specific substring within a larger string and return the starting position of that substring. This is crucial for tasks like data validation, filtering, and extracting specific pieces of information from text fields. For instance, you might need to find the location of a specific keyword in a product description or identify the starting position of a postal code within an address. `CHARINDEX` is particularly useful when you need to perform conditional logic based on the presence or location of a substring. It's important to note that `CHARINDEX` is case-sensitive, meaning it distinguishes between uppercase and lowercase characters. If you need a case-insensitive search, you might need to use additional string functions or techniques like converting the strings to lowercase before searching.