Hi all, Trying to write an SQL query for the Sloan Digital Sky Survey that uses the NOT operator, and failing miserably. Basically, I'm making photometric cuts in 4-d colour space, and I currently have a selection of inequalities that select enclosed regions of colour space. However, I now want to NOT that triangle, and select everything but that triangle, whilst still specifying a simple 'must be bluer than:...' colour cut. The problem is that I can't get the query to return the data with the missing triangle, it simply selects all blue items. This is what I've tried so far: (This is in the WHERE clause) and (P.psfmag_u-P.psfmag_g) < 0.55 and NOT ( (P.psfmag_u-P.psfmag_g) >= (1.27*(P.psfmag_g- P.psfmag_r) + 0.25) and (P.psfmag_u-P.psfmag_g) <= ((3.9*(P.psfmag_g-P.psfmag_r)) + 1.8) and (P.psfmag_g- P.psfmag_r) > (1.6*(P.psfmag_r- P.psfmag_i) - 0.05) and (P.psfmag_g- P.psfmag_r) < (1.28*(P.psfmag_r- P.psfmag_i) + 0.25) and (P.psfmag_g- P.psfmag_r) < (-1.45*(P.psfmag_r- P.psfmag_i) + 0.2) and (P.psfmag_r- P.psfmag_i) > (3.73*(P.psfmag_i- P.psfmag_z) - 0.24) and (P.psfmag_r- P.psfmag_i) < (0.725*(P.psfmag_i- P.psfmag_z) + 0.18) and (P.psfmag_r-P.psfmag_i) between -0.45 and 0.15 and (P.psfmag_i-P.psfmag_z) between -0.6 and 0.1) Any help would be appreciated, I'm relatively new to SQL and I'm struggling to find a workaround. The syntax checks out as being 'ok', but clearly the results aren't.