sql server - how to cast or convert numeric/varchar to date data type field in sql and use in update statement? -

good day!

i have 2 questions how update date data type column field using varchar , numeric column field

1.)mydate varchar(8)--> varchar column field

select mydate mytable 

result: 20141120

my question how can update date column field using varchar column field using cast or convert

update table2 set date = (select mydate mytable) 

which error!!! , i'm stuck.

2.)mydate numeric(8) --> numeric column field

select mydate mytable 

result:

20101015

20140910

etc.......

update table2 set date = (select mydate mytable a, mytable2 b a.id=b.id) 

my question how can update date column field using numeric column field using cast or convert

i used different cast , convert still i'm getting error!

what correct syntax this?

thank your help!

to convert string date field need use convert function:

convert(datetime, mydate, 101) 

this expecting string field, if mydate field numeric field need cast string, convert command like:

convert(datetime, cast(mydate varchar), 101) 

the third parameter of function determined format of date in previous parameter, can find full list on msdn @ http://msdn.microsoft.com/en-us/library/ms187928.aspx