在SQL Server中验证日期格式dd-mmm-yyyy和dd mmm yyyy

Question

I need to validate two date formats: DD-MMM-YYYY and DD MMM YYYY .

Here is the code I use to validate DD-MMM-YYYY

CASE 
   WHEN (date_column != ' ' 
         AND (ISDATE(date_column) = 0
              OR (ISDATE(date_column) = 1
              AND (CHARINDEX('-', date_column, 0) <> 3 
               OR (CHARINDEX('-', date_column, 4) <>7
               OR (LEN(date_column) <> 11))) 
      THEN 1
      ELSE 0  
END)

Here is the code I use to validate DD MMM YYYY:

 CASE WHEN ( date_column !=' ' 
       AND ( ISDATE(date_column )=0
           OR ( ISDATE(date_column )=1
               AND ( CHARINDEX(' ',date_column ,0) <>3 
               OR  ( CHARINDEX(' ',date_column ,4) <>7
               OR  (LEN(date_column) <>11
               )
             )
         ) THEN 1
         ELSE 0  END)

Can these be combined to populate at a same time instead of two blocks of code?

Answer 1

CONVERT the datetime into the format that you want.

https://docs.microsoft.com/en-us/sql/t-sql/functions/cast-and-convert-transact-sql

Example query: SELECT GETDATE(), CONVERT(varchar(10), GETDATE(), 120) Example output: 2018-02-06 14:02:50.900 2018-02-06

Answer 2

try_parse returns NULL when it is not a valid date. German Culture 'de-de' knows the formats 'dd-mm-yyyy' or 'dd mm yyyy'

CASE WHEN TRY_PARSE(date_column AS DATE USING 'de-de') IS NOT NULL 
     THEN 1 
     ELSE 0 
END