sql-server - 从字母数字字段中提取 6-8 位日期

Question

截图说明了一切。 http://i46.tinypic.com/f3hobl.png

在当前配置下，InvoiceSentDate 仅接受 8 位日期 (MM-DD-YY)。我也希望能够捕获 MM-DD-YYYY 日期。我该怎么做？

为了比较，请查看发票 2106-2112 与 2116。

此外，使事情复杂化!有些记录在日期之后有文字。 http://i50.tinypic.com/2r5qa88.png

Answer 1

您可以在纯 T-SQL 中执行此操作。这是工作 SqlFiddle .

在这里，我使用 patindex 查找日期，然后查找其后的第一个非数字。这为 substring 提供了单独提取日期所需的参数。如您所见，我添加了一些测试数据，涵盖了各种可能性，包括斜线和破折号日期分隔符。

-- Test data
declare @Demo table (
    RawData varchar(100) null
)
insert into @Demo select 'JS sent via Unifier on 08/29/2012'
insert into @Demo select 'i sent via email on 09/07/12'
insert into @Demo select 'i sent via Unifier on 01/04/12; resubmitting p...'
insert into @Demo select 'JS sent via Unifier on 08-29-2012; resubmitting p...'
insert into @Demo select '08-29-2012; resubmitting p...'
insert into @Demo select '08-29-12'
insert into @Demo select 'no date here'
insert into @Demo select null

-- Actual query
select *,
    -- If there's a date, display it
    case when StartChar > 0 then substring(RawData, StartChar, DateLen) else null end as DateString 
from (
    select *,
        -- Find the first date
        patindex('%[0-1][0-9][/-][0-3][0-9][/-][0-9][0-9]%', RawData) as StartChar,
        -- Find the first non-digit after that date
        patindex(
            '%[^0-9]%', 
            right(
                RawData + '_', -- This underscore adds at least one non-digit to find
                len(RawData) - patindex('%[0-1][0-9][/-][0-3][0-9][/-][0-9][0-9]%', RawData) - 6
            )
        ) + 7 as DateLen
    from @Demo
) as a

更新

如果您只是在寻找 2 种可能的日期格式，您可以通过检查它们来简化查询:

select *,
    -- If there's a date, display it
    case
        when StartChar1 > 0 then substring(RawData, StartChar1, 10)
        when StartChar2 > 0 then substring(RawData, StartChar2, 8)
        else null
    end as DateString 
from (
    select *,
        -- Find the first MM-DD-YYYY
        patindex('%[0-1][0-9][/-][0-3][0-9][/-][0-9][0-9][0-9][0-9]%', RawData) as StartChar1,
        -- Find the first MM-DD-YY
        patindex('%[0-1][0-9][/-][0-3][0-9][/-][0-9][0-9]%', RawData) as StartChar2
    from @Demo
) as a