What is SQL server concatenation?

Concatenation in SQL servers refers to linking two strings together with the use of the + operator. In order to concatenate two expressions in a Microsoft SQL server, they must be of the same data type or have to be able to be implicitly converted to the other data type.

The + operator can be used to concatenate strings, columns or combinations thereof, as long as the strings are not image, ntext or text data types. When data types cannot be implicitly converted, the user must use the convert or cast functions in order to be able to concatenate the data.