Calculate the maximum storage size of table record

问题:

Is there a way to determine what the maximum size of a record would be in SQL Server past doing it by hand? For example:

CREATE TABLE test (
    id INT PRIMARY KEY IDENTITY(1, 1),
    name VARCHAR(256),
    test_date DATETIME
)

so, if I'm not mistaken, when calculating that by hand that record could be a maximum of 272 bytes. However, I have a table with a lot more columns than that, and I need to do this for more than one table, so I wanted to know if I could do this with a simple query.

I can't find any information in INFORMATION_SCHEMA.TABLES or even INFORMATION_SCHEMA.COLUMNS where I figured I could do a simple SUM for example. Further, sysobjects and syscolumns don't seem to have the necessary information. The syscolumns table does have a length field but that's not the actual storage size.

Thanks all!

回答1:

Try this:

Select  schema_name(T.schema_id) As SchemaName,
        T.Name As TableName,
        Sum(C.max_length) As RowSize
From    sys.tables T
        Inner Join sys.columns C
            ON T.object_id = C.Object_ID
        INNER JOIN sys.types S
            On C.system_type_id = S.system_type_Id
Group By schema_name(T.schema_id),
        T.Name
Order By schema_name(T.schema_id),
        T.Name