abs(N)?返回N的绝对值??
mysql> select ABS(2);????
-> 2????
mysql> select ABS(-32);????
-> 32????
???
sign(N)?返回参数的符号(为-1、0或1)??
mysql> select SIGN(-32);????
-> -1????
mysql> select SIGN(0);????
-> 0????
mysql> select SIGN(234);????
-> 1????
?
mod(N,M)?取模运算,返回N被M除的余数(同%操作符)????
mysql> select MOD(234, 10);????
-> 4????
mysql> select 234 % 10;????
-> 4????
mysql> select MOD(29,9);????
-> 2????
?
floor(N)?返回不大于N的最大整数值??
mysql> select FLOOR(1.23);????
-> 1????
mysql> select FLOOR(-1.23);????
-> -2????
?
ceiling(N)?返回不小于N的最小整数值??
mysql> select CEILING(1.23);????
-> 2????
mysql> select CEILING(-1.23);????
-> -1????
?
round(N, D)?返回N的四舍五入值,保留D位小数(D的默认值为0)??
mysql> select ROUND(-1.23);????
-> -1????
mysql> select ROUND(-1.58);????
-> -2????
mysql> select ROUND(1.58);????
-> 2????
mysql> select ROUND(1.298, 1);????
-> 1.3????
mysql> select ROUND(1.298, 0);????
-> 1????
?
exp(N)返回值e的N次方(自然对数的底)??
mysql> select EXP(2);????
-> 7.389056????
mysql> select EXP(-2);????
-> 0.135335????
?
log(N)?返回N的自然对数??
mysql> select LOG(2);????
-> 0.693147????
mysql> select LOG(-2);????
-> NULL????
?
log10(N)?返回N以10为底的对数??
mysql> select LOG10(2);????
-> 0.301030????
mysql> select LOG10(100);????
-> 2.000000????
mysql> select LOG10(-100);????
-> NULL????
?
pow(X,Y)或power(X,Y)?返回值X的Y次幂??
mysql> select POW(2,2);????
-> 4.000000????
mysql> select POW(2,-2);????
-> 0.250000??
?
sqrt(N)?返回非负数N的平方根??
mysql> select SQRT(4);????
-> 2.000000????
mysql> select SQRT(20);????
-> 4.472136????
?
pi()?返回圆周率???
mysql> select PI();????
-> 3.141593????
?
cos(N)?返回N的余弦值??
mysql> select COS(PI());??
-> -1.000000????
?
sin(N)?返回N的正弦值???
mysql> select SIN(PI());????
-> 0.000000????
?
tan(N)?返回N的正切值??
mysql> select TAN(PI()+1);????
-> 1.557408????
?
acos(N)?返回N反余弦(N是余弦值,在-1到1的范围,否则返回NULL)??
mysql> select ACOS(1);????
-> 0.000000????
mysql> select ACOS(1.0001);????
-> NULL????
mysql> select ACOS(0);????
-> 1.570796????
?
asin(N) ?返回N反正弦值??
mysql> select ASIN(0.2);????
-> 0.201358????
mysql> select ASIN('foo');????
-> 0.000000????
?
atan(N)?返回N的反正切值??
mysql> select ATAN(2);????
-> 1.107149????
mysql> select ATAN(-2);????
-> -1.107149????
atan2(X,Y)?返回2个变量X和Y的反正切(类似Y/X的反正切,符号决定象限)??
mysql> select ATAN(-2,2);????
-> -0.785398????
mysql> select ATAN(PI(),0);????
-> 1.570796????
?
cot(N)?返回X的余切??
mysql> select COT(12);????
-> -1.57267341????
mysql> select COT(0);????
-> NULL????
?
RAND()或RAND(N)?返回在范围0到1.0内的随机浮点值(可以使用数字N作为初始值)?
mysql> select RAND();????
-> 0.5925????
mysql> select RAND(20);????
-> 0.1811????
mysql> select RAND(20);????
-> 0.1811????
mysql> select RAND();????
-> 0.2079????
mysql> select RAND();????
-> 0.7888????
?
degrees(N)?把N从弧度变换为角度并返回??
mysql> select DEGREES(PI());????
-> 180.000000????
?
radians(N)?把N从角度变换为弧度并返回???
mysql> select RADIANS(90);????
-> 1.570796????
?
truncate(N,D)?保留数字N的D位小数并返回??
mysql> select TRUNCATE(1.223,1);????
-> 1.2????
mysql> select TRUNCATE(1.999,1);????
-> 1.9????
mysql> select TRUNCATE(1.999,0);????
-> 1????
?
least(X,Y,...) ?返回最小值(如果返回值被用在整数(实数或大小敏感字串)上下文或所有参数都是整数(实数或大小敏感字串)则他们作为整数(实
数或大小敏感字串)比较,否则按忽略大小写的字符串被比较)??
mysql> select LEAST(2,0);????
-> 0????
mysql> select LEAST(34.0,3.0,5.0,767.0);????
-> 3.0????
mysql> select LEAST("B","A","C");????
-> "A"????
?
greatest(X,Y,...)?返回最大值(其余同LEAST())??
mysql> select GREATEST(2,0);????
-> 2????
mysql> select GREATEST(34.0,3.0,5.0,767.0);????
-> 767.0????
mysql> select GREATEST("B","A","C");????
-> "C"????