当tsql中的值为数字时更新列

您可以始终执行子查询

update table set date = '01.01.' + date
where id in(

   select id from table
   where date like '____' and isnumeric(date)

)
and convert(int, date) >= 1950

用单引号括上1950年怎么样?

我做了一个快速测试:

DECLARE @Table TABLE (Date NVARCHAR(20))
INSERT @Table 
SELECT '2010' 
UNION ALL 
SELECT '2009' 
UNION ALL 
SELECT '01.07.1989' 
UNION ALL 
SELECT '1951'
UNION ALL
SELECT '1940'
UNION ALL
SELECT 'Some Text'

UPDATE @Table
SET Date = '01.01.' + date
WHERE date LIKE '____' AND ISNUMERIC(date) = 1 AND date>='1950'

SELECT * FROM @Table

可能添加一个新字段来存储实际的日期时间值:

alter table [Table] add [RealDate] datetime;
update [Table] set [RealDate] = cast([Date] as datetime) where isdate([Date]) = 1