Figure 2-7 provides the full list of built-in SQL functions that you can overload. A user might create a function with the same name as one from this table, but its routine signature must be unique in the database (non-ANSI) or the schema (ANSI). For more information on a routine signature, refer to "The Routine Signature".

Figure 2-7
Built-In SQL Functions That You Can Overload

(1 of 2)

Built-In SQL Function Names	Number of Parameters	Parameter Types
abs()	1	real number
mod()	2	real number expression, real number expression
pow()	2	real number expression, real number expression
root()	1 or 2	real number expression [, real number expression]
round()	1 or 2	expression, [literal integer]
sqrt()	1	real number expression
trunc()	1 or 2	expression, literal integer
exp(), log(), logn()	1	positive real expression
cos(), sin(),tan()	1	numeric expression
asin(), acos(), atan()	1	numeric expression
atan2	2	numeric expression, numeric expression
length(), octet_length(), char_length(), character_length()	1	character string

These built-in SQL functions appear as UDRs and have entries in the sysprocedures system catalog table. The language for these entries are C or BUILTIN, depending on the internal implementation. Informix strongly recommends that you do not update or delete these entries.

Universal Server does not handle the following built-in SQL functions as UDRs. Therefore, you cannot overload these built-in SQL functions:

• user
• sitename, dbservername
• today
• current
• extend
• trim
• hex
• date
• mdy
• day, month, weekday, year
• dbinfo