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12.6.1 Arithmetic Operators
The usual arithmetic operators are available. The result is determined according to the following rules:
In the case of
-
,+
, and*
, the result is calculated withBIGINT
(64-bit) precision if both operands are integers.If both operands are integers and any of them are unsigned, the result is an unsigned integer. For subtraction, if the
NO_UNSIGNED_SUBTRACTION
SQL mode is enabled, the result is signed even if any operand is unsigned.If any of the operands of a
+
,-
,/
,*
,%
is a real or string value, the precision of the result is the precision of the operand with the maximum precision.In division performed with
/
, the scale of the result when using two exact-value operands is the scale of the first operand plus the value of thediv_precision_increment
system variable (which is 4 by default). For example, the result of the expression5.05 / 0.014
has a scale of six decimal places (360.714286
).
These rules are applied for each operation, such that nested
calculations imply the precision of each component. Hence,
(14620 / 9432456) / (24250 / 9432456)
,
resolves first to (0.0014) / (0.0026)
, with
the final result having 8 decimal places
(0.60288653
).
Because of these rules and the way they are applied, care should be taken to ensure that components and subcomponents of a calculation use the appropriate level of precision. See Section 12.10, “Cast Functions and Operators”.
For information about handling of overflow in numeric expression evaluation, see Section 11.2.6, “Out-of-Range and Overflow Handling”.
Arithmetic operators apply to numbers. For other types of
values, alternative operations may be available. For example, to
add date values, use DATE_ADD()
;
see Section 12.7, “Date and Time Functions”.
Addition:
- -> 8
Subtraction:
- -> -2
Unary minus. This operator changes the sign of the operand.
- -> -2
Multiplication:
- -> 15
- -> 324518553658426726783156020576256.0
- -> out-of-range error
The last expression produces an error because the result of the integer multiplication exceeds the 64-bit range of
BIGINT
calculations. (See Section 11.2, “Numeric Types”.)Division:
- -> 0.60
Division by zero produces a
NULL
result:A division is calculated with
BIGINT
arithmetic only if performed in a context where its result is converted to an integer.Integer division. Discards from the division result any fractional part to the right of the decimal point.
If either operand has a noninteger type, the operands are converted to
DECIMAL
and divided usingDECIMAL
arithmetic before converting the result toBIGINT
. If the result exceedsBIGINT
range, an error occurs.Modulo operation. Returns the remainder of
N
divided byM
. For more information, see the description for theMOD()
function in Section 12.6.2, “Mathematical Functions”.
Document created the 26/06/2006, last modified the 26/10/2018
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