Q:

SQL ISDATE function not working

I have date column in a SQL Server table in two different formats

Format-1: dd/mm/yyyy  
Format-2: yyyy-mm-dd  

I would like to change the format-1 to format 2 but the SQL throws an error.
please advise 
update T1_fact
set wk_date = to_date(varchar, 'yyyy-mm-dd')
where is_date(varchar, 'dd/mm/yyyy') = 1

A:

As commented by @marc --> 

TO_DATE is not a standard SQL function - it's an Oracle specific function which doesn't exist in SQL Server 
So, for SQL Server, you would required to use convert() function in order to update your dates with standard format yyyy-mm-dd
update T1_fact
set wk_date = CONVERT(date, wk_date, 103)
--where is_date(varchar, 'dd/mm/yyyy') = 1

