stddevw_samp.c File Reference

Weighted standard deviation of sample. More...

#include "sqlstat.h"

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Classes
struct	stddevw_samp_storage
	Storage for weighted standard deviation of sample. More...

Functions
my_bool	stddevw_samp_init (UDF_INIT *initid, UDF_ARGS *args, char *message)
	Called before first usage of function. More...
void	stddevw_samp_reset (UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error)
	Reset function and add first group member Calls clear and add. More...
void	stddevw_samp_clear (UDF_INIT *initid, char *is_null, char *error)
	Called at start of group. More...
void	stddevw_samp_add (UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error)
	Add a member of the group. More...
double	stddevw_samp (UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error)
	Retrieve weighted standard deviation of sample. Called at end of group. More...
void	stddevw_samp_deinit (UDF_INIT *initid)
	Called after last access to function. More...

Detailed Description

Weighted standard deviation of sample.

CREATE AGGREGATE FUNCTION stddevw_samp RETURNS REAL SONAME 'libsqlstat.so';
SELECT stddevw_samp(x) FROM mytab;
DROP FUNCTION stddevw_samp;

Definition in file stddevw_samp.c.

Function Documentation

double stddevw_samp	(	UDF_INIT *	initid,
		UDF_ARGS *	args,
		char *	is_null,
		char *	error
	)

Retrieve weighted standard deviation of sample. Called at end of group.

Parameters

initid	function description
args	argument values
is_null	result is NULL
error	error message

Returns

weighted standard deviation of sample

Definition at line 161 of file stddevw_samp.c.

void stddevw_samp_add	(	UDF_INIT *	initid,
		UDF_ARGS *	args,
		char *	is_null,
		char *	error
	)

Add a member of the group.

The counter and sums are updated

Parameters

initid	function description
args	argument values
is_null
error	error message

Definition at line 128 of file stddevw_samp.c.

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void stddevw_samp_clear	(	UDF_INIT *	initid,
		char *	is_null,
		char *	error
	)

Called at start of group.

void stddevw_samp_clear(UDF_INIT *initid, char *is_null, char *error) The counter and sums are cleared.

Parameters

initid	function description
is_null
error	error message

Definition at line 110 of file stddevw_samp.c.

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void stddevw_samp_deinit

(

UDF_INIT *

initid

)

Called after last access to function.

Deallocate memory for counter and sums.

Parameters

initid

Definition at line 191 of file stddevw_samp.c.

my_bool stddevw_samp_init	(	UDF_INIT *	initid,
		UDF_ARGS *	args,
		char *	message
	)

Called before first usage of function.

Check parameters.
Indicate type of return value.
Allocate memory for counter and sums.

Parameters

initid	function description
args	parameters
message	error message

Returns

success = 0

Definition at line 57 of file stddevw_samp.c.

void stddevw_samp_reset	(	UDF_INIT *	initid,
		UDF_ARGS *	args,
		char *	is_null,
		char *	error
	)

Reset function and add first group member Calls clear and add.

Parameters

initid	function description
args	argument values
is_null
error	error message

Deprecated:

Reset is only called by MySQL 4.0 and below. It is implemented for backwards compatibility.

Definition at line 96 of file stddevw_samp.c.

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