Check if bit is set in mysql I have a field which stores the days of the week in binary representation. For example, Mon-Wed-Fri would be represented as b'0101010' with the 1st digit as Sunday and the last as Saturday. 

What I want to achieve: If today is Monday, I want to check if the Monday bit is set to 1. I do that by doing (b'0101010' &amp; b'0100000' > 0). But I am struggling in converting the current date into the corresponding weekday binary representation. How can I achieve so?
The following expression will give the bit representation of today's day of week:

POW(2, 7 - DAYOFWEEK(NOW())



POW(2, n) raises 2 to the nth power, which is the same as shifting 1 n bits from the right.
DAYOFWEEK(date) returns the day of the week as a number, with Sunday = 1.
Since you have the low-numbered dates in the high-order bits, 7 - DOW converts that to Sunday = 6, Saturday = 0.


Wouldn't it be easier to declare the column as a SET, though? Then you could just use FIND_IN_SET().