MS SQL
-- in this sample Dateadd() function retrieve that day befor 7 days by getdate() , then format it to varchar
-- the format as a date of japan yy/mm/dd
-- convert() function format date to 111 as japan date format , like this yyyy/mm/dd
select convert(varchar(20), DATEADD(day, -7, getdate()) ,111)
-- This sample casting date to float and floor the times part to 00:00:00.000
-- so that return the result same as 2008-10-22 00:00:00.000
-- If you trying to compare two datetime, this probably is best choice
SELECT CAST(FLOOR( CAST( GETDATE() AS FLOAT ) )AS DATETIME)
MySQL
-- Format a DATETIME or TIMESTAM to VARCHAR
-- for sample 2009-06-19 13:30:21
DATE_FORMAT(update_date,'%Y-%m-%d %T')
The formats that can be used are:
| Format | Description |
|---|---|
| %a | Abbreviated weekday name |
| %b | Abbreviated month name |
| %c | Month, numeric |
| %D | Day of month with English suffix |
| %d | Day of month, numeric (00-31) |
| %e | Day of month, numeric (0-31) |
| %f | Microseconds |
| %H | Hour (00-23) |
| %h | Hour (01-12) |
| %I | Hour (01-12) |
| %i | Minutes, numeric (00-59) |
| %j | Day of year (001-366) |
| %k | Hour (0-23) |
| %l | Hour (1-12) |
| %M | Month name |
| %m | Month, numeric (00-12) |
| %p | AM or PM |
| %r | Time, 12-hour (hh:mm:ss AM or PM) |
| %S | Seconds (00-59) |
| %s | Seconds (00-59) |
| %T | Time, 24-hour (hh:mm:ss) |
| %U | Week (00-53) where Sunday is the first day of week |
| %u | Week (00-53) where Monday is the first day of week |
| %V | Week (01-53) where Sunday is the first day of week, used with %X |
| %v | Week (01-53) where Monday is the first day of week, used with %x |
| %W | Weekday name |
| %w | Day of the week (0=Sunday, 6=Saturday) |
| %X | Year of the week where Sunday is the first day of week, four digits, used with %V |
| %x | Year of the week where Monday is the first day of week, four digits, used with %v |
| %Y | Year, four digits |
| %y | Year, two digits |
