Встроенные функции языка SQL (диалект Oracle)

 

 

The return values have datatype MLSLABEL. For the definitions of greatest least upper bound and Например: usage, see Trusted Oracle7 Server Administrator's Guide.

 

 

MAX

 

Syntax   MAX([DISTINCT|ALL] expr)

 

Purpose Returns maximum value of expr.

 

Например: SELECT MAX(sal) "Maximum"

FROM emp

 

   Maximum

-----------------

   5004

 

MIN

 

Syntax   MIN([DISTINCT|ALL] expr)

 

Purpose Returns minimum value of expr.

Например: SELECT MIN(hiredate) "Minimum Date"

FROM emp

 

Minimum Date

----------------------

17-DEC-80

Note The DISTINCT and ALL options have no effect on the MAX and MIN functions.

 

STDDEV

 

Syntax   STDDEV([DISTINCT|ALL] x)

 

Purpose Returns standard deviation  of x, a number. Oracle7 calculates the standard deviation as the square root of the variance defined for the VARIANCE group function.

 

Например: SELECT STDDEV(sal) "Deviation"

FROM emp

 

Deviation

-----------------

1182.50322

 

SUM

 

Syntax   SUM([DISTINCT|ALL] n)

 

Purpose Returns sum of values of n.

 

Например: SELECT SUM(sal) "Total"

FROM emp

 

     Total

-------------

     29081

 

VARIANCE

 

Syntax   VARIANCE([DISTINCT|ALL]x)

 

Purpose Returns variance of x, a number. Oracle7 calculates the variance of x using this formula:

 

 

 

 

where:

 

 

xi   is one of the elements of x.

 

n   is the number of elements in the set x. If n is 1, the variance is defined to be 0.

 

Например: SELECT VARIANCE(sal) "Variance"

FROM emp  

 

Variance

-----------------

1389313.87

 

 

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