Take 1 hour from time field

Question

I have an time field which is in string format 'varchar' and I wish to convert this field to a time and take an hour from the converted value so that if I have 14:22 in the field I would get 13:22 in the converted value. How would I do this in a view?

Answer 1

对于SQL Server，可以使用以下查询：

select dateadd(hh,-1 ,cast(timecolumn as time)) from tablename

Answer 2

如果使用MySQL，请使用DATE_SUB减去一个时间段。

SELECT DATE_SUB(timefield, INTERVAL 1 HOUR) AS timefield_minus_hour

Answer 3

This works with MS SQL 2012: Fiddle Demo

SELECT DATEADD(HH,-1 ,CAST(stringTime as time)) FROM myTable