Detect if a date is in Daylight saving time in MySql

Question

I have inherited a legacy application where all the dates and times are stored in the local timezone (UK). I am not in a position to change how these are stored.

Howeve

Answer 1

found an ugly complicated way, @DT is input Date&Time

Set @DT=20150329020304; # -> 0

Set @DT=20150329030304; # -> 1(-0.0511)

Set @DT=20150329040304; # -> 1(-1)

Select 0!=(UNIX_TIMESTAMP(@DT)-   UNIX_TIMESTAMP(Concat(Year(@DT),'0101',Time_Format(@DT,'%H%i%s')))-DateDiff(@DT,Concat(Year(@DT),'0101',Time_Format(@DT,'%H%i%s')))*86400)/3600 as DlsIsOn