Four different data types define text:

You enter character data as alphanumeric strings. You must enclose the string in single quotes ('). To include an explicit single quote (or apostrophe) within a character string, dereference it by preceding it with another single quote. For example:

You can include double quotes within a single‑quoted character string without dereferencing them:

In displaying a query result, SQL displays character data as alphanumeric strings without the surrounding single quotes. SQL differentiates between uppercase and lowercase data in character strings. For example, suppose you use this string in an SQL statement:

It is evaluated differently from any of the strings below: