对于字符串向smalldatetime转换失败问题的解决

此类问题一般出现于动态存储过程，我以up_selectTradeInfo为例简单说明该问题的解决方法 

--建表--银行卡表GOUSE BankCardManageDBGOIF EXISTS (SELECT * FROM sys.objects WHERE NAME='BankCard') DROP TABLE BankCardCREATE TABLE BankCard  ( ID int identity(1,1), CardID char(10) PRIMARY KEY, BankName varchar(20) NOT NULL, UserName varchar(20) NOT NULL, Deposit money NOT NULL DEFAULT(0), Payout money NOT NULL DEFAULT(0))GO
--交易记录表USE BankCardManageDBIF EXISTS(SELECT * FROM sys.objects WHERE NAME='Trade') DROP TABLE TradeCREATE TABLE Trade  ( TradeID BIGINT PRIMARY KEY IDENTITY(1,1), CardID CHAR(10) FOREIGN KEY REFERENCES BankCard(CardID) NOT NULL, TradeDate DATETIME NOT NULL, TradeMoney MONEY CHECK(TradeMoney>0), TradeType char(8) CHECK(TradeType='存钱' or TradeType='取钱'))GO
--插入测试数据INSERT INTO BankCard VALUES('123456766','工商银行','田国兴',2000,200)INSERT INTO Trade VALUES('123456766','20080921',30000,'存钱')
--创建存储过程 up_selectTradeInfo 查询时间段内卡的交易信息
USE BankCardManageDB
GOIF EXISTS(SELECT * FROM sys.objects WHERE name='up_selectTradeInfo') DROP PROCEDURE up_selectTradeInfoGOCREATE PROCEDURE up_selectTradeInfo @cardID varchar(10), @startDate smalldatetime,--时间上限 @endDate smalldatetime --时间下限AS  BEGIN DECLARE @sqlStr varchar(300) SET @sqlStr='SELECT * FROM Trade WHERE CardID='+str(@cardID) +' AND TradeDate BETWEEN '+@startDate+' AND '+@endDate EXEC(@sqlStr) END
exec up_selectTradeInfo '123456766','20080920','20080921'

在执行存储过程时，发生以下错误消息 295，级别 16，状态 3，过程 up_selectTradeInfo，第 11 行将字符串转换为 smalldatetime 数据类型时失败。
具体解决办法如下：把存储过程里面的SET @sqlStr一句改为（嵌套转换）SET @sqlStr='SELECT * FROM Trade WHERE CardID='+str(@cardID) +' AND TradeDate BETWEEN CONVERT(SMALLDATETIME,'+''''+CONVERT(VARCHAR,@startDate,112)+''''+',120)' +' AND CONVERT(SMALLDATETIME,'+''''+CONVERT(VARCHAR,@endDate,112)+''''+',120)'(注意：在数据类型为datetime时最好不要使用那个BETWEEN)再执行exec up_selectTradeInfo '123456766','20080920','20080921'返回TradeID              CardID     TradeDate               TradeMoney            TradeType-------------------- ---------- ----------------------- --------------------- ---------18                   123456766  2008-09-21 00:00:00     30000.00              存钱    
(1 行受影响)问题解决！！