Can I convert a bunch of boolean columns to a single bitmap in PostgreSQL?

Question

I\'d like to convert a query such as:

SELECT BoolA, BoolB, BoolC, BoolD FROM MyTable;

Into a bitmask, where the bits are defined by the val

Answer 1

Maybe like this:

SELECT
  (CASE WHEN BoolA THEN 1 ELSE 0 END << 0) +
  (CASE WHEN BoolB THEN 1 ELSE 0 END << 1) +
  (CASE WHEN BoolC THEN 1 ELSE 0 END << 2) +
  (CASE WHEN BoolD THEN 1 ELSE 0 END << 3) AS BitMask
FROM MyTable;

where << is the bitwise shift left operator.