The two most commonly used variables data types in any given programming language are strings and integers. Nonetheless, these data type formats are also universally applicable to scripting languages such as SQL because the underlying logic behind them is exactly identical. So, to put it simply, a variable that is initialized as a string data type will not be able to perform any numerical calculations. By default, these string numerical values are treated as a text, which means they are considered a word rather than an integer or float-point numerical digits. Therefore, if we try to use any logical or mathematical expressions with these values, it will most definitely result in a compiling or execution error. However, as we have discussed in the previous chapter, this issue can be quickly remediated by using the cast or convert functions to convert those numerical string values into a proper integer or float-point values for calculations.