The constants TRUE and
FALSE evaluate to 1 and
0, respectively. The constant names can be
written in any lettercase.
mysql> SELECT TRUE, true, FALSE, false;
-> 1, 1, 0, 0
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User Comments
TRUE converts to 1 and FALSE converts to 0 during query parsing, therefore those two values behave exactly like the respective numbers, e.g. TRUE + TRUE = 2 and FALSE is not NULL.
I suggest using "ENUM('on') NULL" for representing boolean values. This should work well with HTML checkboxes, which are submitted like x=on or as nothing (read undef in Perl, what correspond to NULL in SQL).
MaryOldEnough AND JaneOldEnough = SeatParty
true AND true = true; 1*1=1
true AND false = false; 1*0=0
false AND false = false; 0*0=0
MaryIsMember OR JaneIsMember = SeatParty
true OR true = true; 1+1=1
true OR false = true; 1+0=1
false OR false = false; 0+0=0
Is there a counter-argument that suggests substituting other non-zero integers would be detrimental?
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