Logical Operators - Oracle 5.0 Reference Manual

This happens because MySQL reads
representation is not good enough to hold the value, so it wraps to a signed integer.

12.3.3. Logical Operators

Table 12.4. Logical Operators
Name
[880]
AND, &&
[880]
NOT, !
[881]
||, OR
[881]
XOR
In SQL, all logical operators evaluate to TRUE, FALSE, or
implemented as 1 (TRUE), 0 (FALSE), and NULL. Most of this is common to different SQL database
servers, although some servers may return any nonzero value for TRUE.
MySQL evaluates any nonzero,
assess to TRUE:
mysql> SELECT 10 IS TRUE;
-> 1
mysql> SELECT -10 IS TRUE;
-> 1
mysql> SELECT 'string' IS NOT NULL;
-> 1
• [880],
NOT
Logical NOT. Evaluates to
returns NULL.
mysql> SELECT NOT 10;
-> 0
mysql> SELECT NOT 0;
-> 1
mysql> SELECT NOT NULL;
-> NULL
mysql> SELECT ! (1+1);
-> 0
mysql> SELECT ! 1+1;
-> 1
The last example produces
Note that the precedence of the
"Operator
• [880],
AND
Logical AND. Evaluates to
are 0, otherwise
mysql> SELECT 1 && 1;
-> 1
mysql> SELECT 1 && 0;
-> 0
mysql> SELECT 1 && NULL;
-> NULL
mysql> SELECT 0 && NULL;
-> 0
mysql> SELECT NULL && 0;
-> 0
non-NULL
[880]
!
if the operand is 0, to
1
because the expression evaluates the same way as (!1)+1.
1
NOT
Precedence".
[880]
&&
if all operands are nonzero and not NULL, to
1
is returned.
NULL
Logical Operators
9223372036854775808.0
Description
Logical AND
Negates value
Logical OR
Logical XOR
NULL
value to TRUE. For example, the following statements all
if the operand is nonzero, and
0
[880] operator changed in MySQL 5.0.2. See
880
in an integer context. The integer
(UNKNOWN). In MySQL, these are
NOT NULL
Section 12.3.1,
if one or more operands
0