ALPHA(x,n)
ALPHA(x,n)
is a string function that enables a character x
(string specification) in ASCII
to be converted
to a different one or two-character representation defined in the DEFAULTMAP
(mapchar_set_name). Only expressions that produce an alphanumeric value are permitted as string specifications x
.
ALPHA(x,n)
is used to define the sort sequence.
The function ALPHA(x,n)
uses the MAPCHAR(x,n,i) function internally (where i
is the DEFAULTMAP
) and also
performs a conversion to uppercase letters via UPPER(y) (where y
is MAPCHAR(x,n,i)
).
The code on which the character x
is based and the code on which the implemented DEFAULTMAP
(defined for the ASCII
code) is based must match. In Unicode-based database systems string specifications
are Unicode. So if necessary convert the string specification to an ASCII
expression (using for example the function ASCII(x)
).
x, n |
Result of the ALPHA(x,n) Function |
|---|---|
|
|
Specifying n
(an entire number without a sign) is optional. n
specifies the maximum length of the result.
Example
The ALPHA
function allows a useful sorting process, for example, when "ü" should be sorted as "UE". The mapchar set with the name DEFAULTMAP
is used.
SELECT ...,ALPHA(<column_name>) sort, ... FROM ... ORDER BY sort