sql - 从字符串转换日期和/或时间时转换失败

Question

我有这个查询:

set IDENTITY_INSERT dbo.OtherData1 ON


INSERT INTO OtherData1 (OtherDataID, EmployeeID, OtherDate, OType, OSubject, StatementNo, StatementDate, Info, OtherAs, FolderSerial)

    SELECT OtherDataID, EmployeeID, 
                 CONVERT(DATE, OtherDate, 103), 
                     OType, OSubject, StatementNo, 
                     CONVERT(DATE, StatementDate), Info,
                     CASE OtherAs
           WHEN  'f' THEN 1
              WHEN  's' THEN 2
              WHEN 't' THEN 3
              WHEN 'f' THEN 4
              WHEN 'p' THEN 5
              WHEN 'o' THEN 6
           ELSE NULL END
           , FolderSerial
    FROM OtherData

当我执行它时，我收到此错误:

Msg 241, Level 16, State 1, Line 5
Conversion failed when converting date and/or time from character string.

StatementDate、OtherDate 的值采用此格式“31/1/1994” 作为转换前的字符串

问题是什么？

编辑:

如果我添加这行代码:

CASE WHEN ISDATE(OtherDate) = 1 THEN 
  CONVERT(DATE, OtherDate, 103)
ELSE NULL END

我尝试了它，但它不起作用，我需要类似的东西来检查如果不插入 NULL 值，是否可以进行转换，并且我收到相同的错误消息

Answer 1

ISDATE 不起作用，因为您甚至无法像使用 CONVERT 那样指定日期格式。以下是一个非常复杂的测试，用于将有效日期重新格式化为 YYYYMMDD，ISDATE 可以按预期工作。

with otherdata(StatementDate) as (
select convert(varchar(10),'1/10/2011') union all
select '28/2/2911' union all
select '8/12/2011' union all
select '13/13/2011' union all
select '13/12/2011' union all
select '12/13/2011' union all
select '2/29/2011' union all
select '29/2/2011' union all
select '29/2/2012' union all
select '2011-02-01' union all
select '1/1/11' union all
select '1/1/99' union all
select '' union all
select null)

-- THE QUERY YOU NEED is below this line. The above virtually sets up a table
-- without having to physically create it
select
    statementdate,
    YYYYMMDDToTest,
    ISDate(YYYYMMDDToTest)
from otherdata
cross apply
       (
       select TheYear = case
       when not statementdate like '%[0-9]/%[0-9]/%[0-9][0-9]' then null
       when convert(int,replace(statementdate,'/','')) != replace(statementdate,'/','') then null
       when statementdate like '%[0-9]/%[0-9]/[0-9][0-9]' then
           case when RIGHT(statementdate,2) >=50
           then '19'+RIGHT(statementdate,2)
           else '20'+RIGHT(statementdate,2)
           end
       when statementdate like '%[0-9]/%[0-9]/[1-9][0-9][0-9][0-9]' then
           RIGHT(statementdate,4)
       end
       ) A
cross apply
       (
       select YYYYMMDDToTest = case
       when TheYear is not null then
           TheYear
           + -- month
           right(100+SUBSTRING(statementdate, charindex('/',statementdate) +1,
           charindex('/',statementdate,charindex('/',statementdate)+1)-
           charindex('/',statementdate)-1),2)
           + -- day
           right(100+LEFT(statementdate, charindex('/', StatementDate) -1),2)
       end
       ) B
WHERE ISDate(YYYYMMDDToTest) = 0

注释掉最后一行 WHERE ISDate(YYYYMMDDToTest) = 0 以查看它对每个日期的作用。

---

编辑

您可以将其转换为替换 ISDATE 的函数 - 但适用于SPECIFIC 格式 [d]d/[m]m/yyyy。

create function dbo.superIs103Date(@any varchar(50))
returns bit as begin
declare @theyear varchar(10)
set @TheYear = case
       when not @any like '%[0-9]/%[0-9]/%[0-9][0-9]' then null
       when convert(int,replace(@any,'/','')) != replace(@any,'/','') then null
       when @any like '%[0-9]/%[0-9]/[0-9][0-9]' then
           case when RIGHT(@any,2) >=50
           then '19'+RIGHT(@any,2)
           else '20'+RIGHT(@any,2)
           end
       when @any like '%[0-9]/%[0-9]/[1-9][0-9][0-9][0-9]' then
           RIGHT(@any,4)
       end
declare @YYYYMMDDToTest varchar(50)
set @YYYYMMDDToTest = case
       when @TheYear is not null then
           @TheYear
           + -- month
           right(100+SUBSTRING(@any, charindex('/',@any) +1,
           charindex('/',@any,charindex('/',@any)+1)-
           charindex('/',@any)-1),2)
           + -- day
           right(100+LEFT(@any, charindex('/', @any) -1),2)
       end
return ISDate(@YYYYMMDDToTest)
end
GO

-- example usage
select dbo.superIs103Date('33/1/1700')
-- returns 0