当我没有要求时，SQL错误将数据转换为Int

Question

I have the following SQL statement. In it I need to convert some numbers stored as varchar to decimal in order to sum them.

When I run this SQL against my constraints I get this message:

Msg 245, Level 16, State 1, Line 1 Conversion failed when converting the varchar value '1635.34' to data type int.

Which baffles me because I am casting my data as decimal. It also baffles me because when I use different constraints that have the same type of data in the field ( 1234.56 type of format) it works. That data is in the TotalPremium field.

(My logic is a bit complex so that is why SQL statement is complex. I am posting all of it for clarity sake. Also, redesigning database table field type is not an option at this point.)

SELECT Account_No, version_num, LineOfBus, ProductNo, QuoteNo, Sum(Cast(TotalPremium as Decimal(16,2))) TotalPremium
    FROM 
    (SELECT t.Account_No, t.version_num, 
        CASE 
            WHEN t.PackageIndicator = '1' THEN 'Package' Else t.Lob 
        END AS LineOfBus,
        t.ProductNo, t.QuoteNo, Cast(COALESCE(t.TotalPremium,0) as decimal(16,2)) TotalPremium 
        FROM uAccountProductInfo as T
        WHERE t.version_num IN
            (SELECT sqVersionNumber.version_num
                FROM
                /* this captures unique package product records (or just stand alone records as well) */
                (SELECT DISTINCT sqUnique.version_num, Count(sqUnique.version_num) VersionCount 
                    FROM
                    /* grab list of all uniquer version, product, quote combinations (use distinct to combine package */
                        (SELECT DISTINCT version_num, productNo, quoteNo
                            FROM uAccountProductInfo
                            WHERE Account_No = '1172014' /* pass as parameter */
                                AND ProductNo IN ('6472930', '6474927') /* pass as parameter */
                                AND QuoteNo IN ('724185-01', '881957-08') /* pass as parameter */
                        ) AS sqUnique
                    GROUP BY version_num
                    HAVING Count(version_num) = 2 /* pass as variable based on number of products, quotes */
                ) as sqVersionNumber
            )
        AND t.Account_no = '1172014' /* pass as parameter */
        AND t.ProductNo IN ('6472930', '6474927') /* pass as parameter */
        AND t.QuoteNo IN ('724185-01', '881957-08') /* pass as parameter */) as sqLOB
    GROUP BY Account_No, version_num, LineOfBus, ProductNo, QuoteNo

Answer 1

Cast t.TotalPremium to decimal before coalescing. Your query is doing coalesce on a string and an integer, then casting the result to decimal. Try using 0.0 instead of 0 as well.

edit I do not actually think using 0.0 rather than 0 is a good idea, aside from readability. If that is the goal, cast it to the same decimal datatype. Otherwise, this could be construed as a datatype dominant over decimal . 0 as int or varchar should not take precedence over our value casted to a decimal.

Answer 2

You could use isnull() instead of coalesce() , though it would still be better practice to use the same datatype as RexMaison points out.

create table t (TotalPremium varchar(16));
insert into t values (''),(null),('1635.34');

/* no error */
select isnull(t.TotalPremium,0) 
from t;

/* no error */
select coalesce(t.TotalPremium,'0')
from t;

/* error */
select coalesce(t.TotalPremium,0) 
from t;

rextester demo: http://rextester.com/OHEJ71310

Answer 3

The problem is that SQL Server does not guarantee the order of evaluation of operations. You clearly have something improper in the field. In SQL Server 2012+, use try_convert() :

SELECT Sum(try_convert(decimal(16, 2), TotalPremium ))) as TotalPremium

In earlier versions, use case :

SELECT Sum(case when isnumeric(TotalPremium) = 1 then  convert(decimal(16, 2), TotalPremium)) end) as TotalPremium

isnumeric() is not perfect, but it should be good enough for your purposes.

Answer 4

Just posting final code that worked after incorporating elements of all 3 answers.

SELECT Account_No, version_num, LineOfBus, ProductNo, QuoteNo, 
        SUM(CASE 
            WHEN ISNUMERIC(TotalPremium) = 1 THEN CONVERT(decimal(16,2),TotalPremium) 
            END) As TotalPremium 
    FROM 
    (SELECT t.Account_No, t.version_num, 
        CASE 
            WHEN ISNull(t.PackageIndicator,'0') = '1' THEN 'Package' Else t.Lob 
        END AS LineOfBus,
        t.ProductNo, t.QuoteNo, 
        ISNull(CASE 
                    WHEN ISNUMERIC(t.TotalPremium) = 1 THEN CONVERT(decimal(16,2),t.TotalPremium) 
                END, 0) TotalPremium 
        FROM uAccountProductInfo as T
        WHERE t.version_num IN
            (SELECT sqVersionNumber.version_num
                FROM
                /* this captures unique package product records (or just stand alone records as well) */
                (SELECT DISTINCT sqUnique.version_num, Count(sqUnique.version_num) VersionCount 
                    FROM
                    /* grab list of all uniquer version, product, quote combinations (use distinct to combine package */
                        (SELECT DISTINCT version_num, productNo, quoteNo
                            FROM uAccountProductInfo
                            WHERE Account_No = '1172014' /* pass as parameter */
                                AND ProductNo IN ('6472930', '6474927') /* pass as parameter */
                                AND QuoteNo IN ('724185-01', '881957-08') /* pass as parameter */
                        ) AS sqUnique
                    GROUP BY version_num
                    HAVING Count(version_num) = 2 /* pass as variable based on number of products, quotes */
                ) as sqVersionNumber
            )
        AND t.Account_no = '1172014' /* pass as parameter */
        AND t.ProductNo IN ('6472930', '6474927') /* pass as parameter */
        AND t.QuoteNo IN ('724185-01', '881957-08') /* pass as parameter */) as sqLOB
    GROUP BY Account_No, version_num, LineOfBus, ProductNo, QuoteNo