Character Datatypes

Use the character datatypes to store strings of letters, numbers, and symbols entered within single or double quotes.

Use the like keyword to search these strings for particular characters, and the built-in string functions to manipulate their contents. Use the convert function to convert strings consisting of numbers to exact and approximate numeric datatypes, which can then be used for arithmetic.

The char(n) datatype stores fixed-length strings, and the varchar(n) datatype stores variable-length strings, in single-byte character sets such as English. Their international character counterparts, nchar(n) and nvarchar(n), store fixed- and variable-length strings in multibyte character sets such as Japanese.The unichar and univarchar datatypes store Unicode characters, which are a constant size. You can specify the maximum number of characters with n or use the default column length of one character. For strings larger than the page size, use the text datatype.




Fixed-length data, such as social security numbers or postal codes


Data, such as names, that is likely to vary greatly in length


Fixed-length Unicode data, comparable to char


Unicode data that is likely to vary greatly in length, comparable to varchar


Fixed-length data in multibyte character sets


Variable-length data in multibyte character sets


Up to 2,147,483,647 bytes of printable characters on linked lists of data pages


Up to 1,073,741,823 Unicode characters on linked lists of data pages

SAP ASE truncates entries to the specified column length without warning or error, unless you set string_rtruncation on. See the Reference Manual: Commands. The empty string, “ ”or ‘ ’, is stored as a single space rather than as NULL. Thus, “abc” + “ ” + “def” is equivalent to “abc def”, not to “abcdef”.

Fixed- and variable-length columns behave somewhat differently: