C*******e 发帖数: 41 | 1 I have a question here:
What do CAST and MULTISET do in SQL language?
I read in a book that CAST converts a specified scalar value to
a specified scalar data type (maybe a user defined data type),
is that true? Does it take at least two arguments (value and the
data type)?
And I can't find MULTISET. Please give me a hand.
Thanks. | s*****c 发帖数: 36 | 2
CAST is a reversed word in SQL2 Standard. Generaly, it
should have two
argus: value and new data type. But in diffrent DBMSs, the
syntax maybe a little diffrent, so you'd better refer to
your server's documents. Convert is another funtion similar
with Cast.
For SQL Server, the syntax is: CAST(expression as datatype),
and it doesn't suporrt user-defined datatype in CAST.
【在 C*******e 的大作中提到】 : I have a question here: : What do CAST and MULTISET do in SQL language? : I read in a book that CAST converts a specified scalar value to : a specified scalar data type (maybe a user defined data type), : is that true? Does it take at least two arguments (value and the : data type)? : And I can't find MULTISET. Please give me a hand. : Thanks.
| C*******e 发帖数: 41 | 3 Thanks!
Since I was looking at relational/object DBMS, CAST
now is extended to user defined data type also, I guess,
in SQL extensions. And probabely MULTISET serves similar
function together with CAST, but I really couldn't find
this guy.
【在 s*****c 的大作中提到】 : : CAST is a reversed word in SQL2 Standard. Generaly, it : should have two : argus: value and new data type. But in diffrent DBMSs, the : syntax maybe a little diffrent, so you'd better refer to : your server's documents. Convert is another funtion similar : with Cast. : For SQL Server, the syntax is: CAST(expression as datatype), : and it doesn't suporrt user-defined datatype in CAST.
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