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substring(), ASE String Function
The
string function
substring()
returns a fragment of a
string
The length and position of the return string (return value) is specified in the
parameters
"start" and "length".
Syntax of the String Function substring()
substring ( expression, start, length )
The parameters of the String Function substring()
"expression"
A part or substring of the value specified in the parameter "expression" is extracted and returned.
The parameter must be set in single or double quotes. It can be a
column name,
variable
or
constant
and must be of one of the
datatypes
char,
varchar,
nchar,
nvarchar,
binary
or
varbinary
If the value of the parameter "expression" is
NULL
then the return value is also NULL.
"start"
The parameter "start" specifies the position of the first character of the string to be returned.
A negative value for the parameter "start" returns NULL.
"length"
The parameter "length" specifies the length of the fragment to be returned, i.e. it
specifies the length of the substring.
A negative value for the parameter "length" returns NULL.
Example for the String Function substring()
select substring("abcdefg", 2, 3)
go
------
bcd
Returns the string fragment "bcd".
select substring("abcdefg", -2, 3)
go
------
NULL
Returns NULL.
select substring("abcdefg", 2, NULL)
go
------
NULL
Returns NULL.
select substring("abcdefg", NULL, 3)
go
------
NULL
Returns NULL.
select substring(NULL, 2, 3)
go
------
NULL
Returns NULL.
select substring("abcdefg", 2, -3)
go
Msg 536, Level 16, State 1:
Server 'ASE_SERVER_NAME', Line 1:
Invalid length parameter with value of -3 passed to the substring function.
Command has been aborted.
------
(0 rows affected)
Returns an error message.
See also:
ASE T-SQL - Aggregate Functions,
ascii(),
char(),
char(n),
charindex(),
char_length(),
compare(),
difference(),
lower(),
ltrim(),
patindex(),
replicate(),
reverse(),
right(),
rtrim(),
sortkey(),
soundex(),
space(),
str(),
String Functions,
stuff(),
to_unichar(),
uhighsurr(),
ulowsurr(),
upper(),
uscalar().
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