Oracle PL/SQL/Analytical Functions/STDDEV SAMP

STDDEV_SAMP(expr) [OVER(analytic_clause)]: computes the cumulative sample standard deviation

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SQL> SQL> SQL> create table TestTable (

 2    x    number primary key,
 3    y    number
 4  );

Table created. SQL> insert into TestTable values (1, 7 ); 1 row created. SQL> insert into TestTable values (2, 1 ); 1 row created. SQL> insert into TestTable values (3, 2 ); 1 row created. SQL> insert into TestTable values (4, 5 ); 1 row created. SQL> insert into TestTable values (5, 7 ); 1 row created. SQL> insert into TestTable values (6, 34 ); 1 row created. SQL> insert into TestTable values (7, 32 ); 1 row created. SQL> insert into TestTable values (8, 43 ); 1 row created. SQL> insert into TestTable values (9, 87 ); 1 row created. SQL> SQL> select * from TestTable;

        X          Y

---

----------

        1          7
        2          1
        3          2
        4          5
        5          7
        6         34
        7         32
        8         43
        9         87

9 rows selected. SQL> SQL> --STDDEV_SAMP(expr) [OVER(analytic_clause)]: computes the cumulative sample standard deviation.

    --It gives the square root of the sample variance.

SQL> SQL> --STDDEV_SAMP(expr) [OVER(analytic_clause)] SQL> SQL> SELECT STDDEV_SAMP(y) FROM TestTable; STDDEV_SAMP(Y)

---

   28.3847573

SQL> SQL> drop table TestTable; Table dropped. SQL> SQL> SQL> SQL>

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