I noticed that I can write
SELECT CAST(Min(mynumber) AS VARCHAR(Max))+'mystring' AS X
as
SELECT CAST(Min(mynumber) AS VARCHAR)+'mystring' X
Will I regret leaving out the (Max) parameter?
views:
69answers:
3
+7
A:
You'll regret it in the (unlikely) situation that MAX(mynumber) has more than 30 characters:
When n is not specified when using the
CASTandCONVERTfunctions, the default length is 30.
LukeH
2010-06-28 14:06:31
Always a good idea to define the number of characters in a situation where you are casting. Or if you are defining a variable (where the default is 1 for varchar). This should just be second nature.
HLGEM
2010-06-28 14:26:00
+2
A:
VARCHAR(MAX) should be used for Large Objects.It uses the normal datapages until the content actually fills 8k of data. When overflow happens, data is stored as old TEXT, IMAGE and a pointer is replacing the old content. Varchar is for Variable-length, non-Unicode character data. n can be a value from 1 through 8,000. Max indicates that the maximum storage size is 2^31-1 bytes. Hope it helps.
prabhats.net
2010-06-28 14:19:02
Yes and varchar (Max) should not ever be used for fields that expect smaller data as it has indexing issues.
HLGEM
2010-06-28 14:22:20
+2
A:
When a varchar's lenght is not specified in a data definition or variable declaration statement, the default length is 1. When it is not specified when using the CAST and CONVERT functions, the default length is 30.
See: char and varchar (Transact-SQL)
I feel that it is poor practice to code without specifying a length for varchar.
KM
2010-06-28 14:25:47