The LENGTH() function


Informix provides the LENGTH() function to count the number of bytes of a character string expression:

SELECT LENGTH("aaa"), LENGTH(col1) FROM table 

Informix LENGTH() does not count the trailing blanks for CHAR or VARCHAR expressions, while Oracle counts the trailing blanks.

Informix LENGTH() returns 0 when the given string is empty. That means, LENGTH('')=0.

Microsoft™ SQL Server

Microsoft SQL Server supports the LEN() function, but there are some differences with Informix LENGTH().

Note: Do not confuse LEN() with DATALEN(), which returns the data size used for storage (number of bytes).

Like Informix, Microsoft SQL Server ignores trailing blanks when computing the length of a string.

When passing NULL as parameter, the SQL Server LEN() function returns NULL.


The database driver is able to replace LENGTH() by the LEN() function name.

The translation of LENGTH() expressions can be controlled with the following FGLPROFILE entry:
dbi.database.dsname.ifxemul.length = { true | false }
For more details see IBM Informix emulation parameters in FGLPROFILE.