Statistical aggregate functions

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The following statistical aggregate functions are available in Google Standard SQL. To learn about the syntax for aggregate function calls, see Aggregate function calls.

CORR

CORR(
  X1, X2
)
[ OVER over_clause ]

over_clause:
  { named_window | ( [ window_specification ] ) }

window_specification:
  [ named_window ]
  [ PARTITION BY partition_expression [, ...] ]
  [ ORDER BY expression [ { ASC | DESC }  ] [, ...] ]
  [ window_frame_clause ]

Description

Returns the Pearson coefficient of correlation of a set of number pairs. For each number pair, the first number is the dependent variable and the second number is the independent variable. The return result is between -1 and 1. A result of 0 indicates no correlation.

All numeric types are supported. If the input is NUMERIC or BIGNUMERIC then the internal aggregation is stable with the final output converted to a FLOAT64. Otherwise the input is converted to a FLOAT64 before aggregation, resulting in a potentially unstable result.

This function ignores any input pairs that contain one or more NULL values. If there are fewer than two input pairs without NULL values, this function returns NULL.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

To learn more about the OVER clause and how to use it, see Window function calls.

Return Data Type

FLOAT64

COVAR_POP

COVAR_POP(
  X1, X2
)
[ OVER over_clause ]

over_clause:
  { named_window | ( [ window_specification ] ) }

window_specification:
  [ named_window ]
  [ PARTITION BY partition_expression [, ...] ]
  [ ORDER BY expression [ { ASC | DESC }  ] [, ...] ]
  [ window_frame_clause ]

Description

Returns the population covariance of a set of number pairs. The first number is the dependent variable; the second number is the independent variable. The return result is between -Inf and +Inf.

All numeric types are supported. If the input is NUMERIC or BIGNUMERIC then the internal aggregation is stable with the final output converted to a FLOAT64. Otherwise the input is converted to a FLOAT64 before aggregation, resulting in a potentially unstable result.

This function ignores any input pairs that contain one or more NULL values. If there is no input pair without NULL values, this function returns NULL. If there is exactly one input pair without NULL values, this function returns 0.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

To learn more about the OVER clause and how to use it, see Window function calls.

Return Data Type

FLOAT64

COVAR_SAMP

COVAR_SAMP(
  X1, X2
)
[ OVER over_clause ]

over_clause:
  { named_window | ( [ window_specification ] ) }

window_specification:
  [ named_window ]
  [ PARTITION BY partition_expression [, ...] ]
  [ ORDER BY expression [ { ASC | DESC }  ] [, ...] ]
  [ window_frame_clause ]

Description

Returns the sample covariance of a set of number pairs. The first number is the dependent variable; the second number is the independent variable. The return result is between -Inf and +Inf.

All numeric types are supported. If the input is NUMERIC or BIGNUMERIC then the internal aggregation is stable with the final output converted to a FLOAT64. Otherwise the input is converted to a FLOAT64 before aggregation, resulting in a potentially unstable result.

This function ignores any input pairs that contain one or more NULL values. If there are fewer than two input pairs without NULL values, this function returns NULL.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

To learn more about the OVER clause and how to use it, see Window function calls.

Return Data Type

FLOAT64

STDDEV_POP

STDDEV_POP(
  [ DISTINCT ]
  expression
)
[ OVER over_clause ]

over_clause:
  { named_window | ( [ window_specification ] ) }

window_specification:
  [ named_window ]
  [ PARTITION BY partition_expression [, ...] ]
  [ ORDER BY expression [ { ASC | DESC }  ] [, ...] ]
  [ window_frame_clause ]

Description

Returns the population (biased) standard deviation of the values. The return result is between 0 and +Inf.

All numeric types are supported. If the input is NUMERIC or BIGNUMERIC then the internal aggregation is stable with the final output converted to a FLOAT64. Otherwise the input is converted to a FLOAT64 before aggregation, resulting in a potentially unstable result.

This function ignores any NULL inputs. If all inputs are ignored, this function returns NULL.

If this function receives a single non-NULL input, it returns 0.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

To learn more about the OVER clause and how to use it, see Window function calls.

Return Data Type

FLOAT64

STDDEV_SAMP

STDDEV_SAMP(
  [ DISTINCT ]
  expression
)
[ OVER over_clause ]

over_clause:
  { named_window | ( [ window_specification ] ) }

window_specification:
  [ named_window ]
  [ PARTITION BY partition_expression [, ...] ]
  [ ORDER BY expression [ { ASC | DESC }  ] [, ...] ]
  [ window_frame_clause ]

Description

Returns the sample (unbiased) standard deviation of the values. The return result is between 0 and +Inf.

All numeric types are supported. If the input is NUMERIC or BIGNUMERIC then the internal aggregation is stable with the final output converted to a FLOAT64. Otherwise the input is converted to a FLOAT64 before aggregation, resulting in a potentially unstable result.

This function ignores any NULL inputs. If there are fewer than two non-NULL inputs, this function returns NULL.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

To learn more about the OVER clause and how to use it, see Window function calls.

Return Data Type

FLOAT64

STDDEV

STDDEV(
  [ DISTINCT ]
  expression
)
[ OVER over_clause ]

over_clause:
  { named_window | ( [ window_specification ] ) }

window_specification:
  [ named_window ]
  [ PARTITION BY partition_expression [, ...] ]
  [ ORDER BY expression [ { ASC | DESC }  ] [, ...] ]
  [ window_frame_clause ]

Description

An alias of STDDEV_SAMP.

VAR_POP

VAR_POP(
  [ DISTINCT ]
  expression
)
[ OVER over_clause ]

over_clause:
  { named_window | ( [ window_specification ] ) }

window_specification:
  [ named_window ]
  [ PARTITION BY partition_expression [, ...] ]
  [ ORDER BY expression [ { ASC | DESC }  ] [, ...] ]
  [ window_frame_clause ]

Description

Returns the population (biased) variance of the values. The return result is between 0 and +Inf.

All numeric types are supported. If the input is NUMERIC or BIGNUMERIC then the internal aggregation is stable with the final output converted to a FLOAT64. Otherwise the input is converted to a FLOAT64 before aggregation, resulting in a potentially unstable result.

This function ignores any NULL inputs. If all inputs are ignored, this function returns NULL.

If this function receives a single non-NULL input, it returns 0.

To learn more about the OVER clause and how to use it, see Window function calls.

Return Data Type

FLOAT64

VAR_SAMP

VAR_SAMP(
  [ DISTINCT ]
  expression
)
[ OVER over_clause ]

over_clause:
  { named_window | ( [ window_specification ] ) }

window_specification:
  [ named_window ]
  [ PARTITION BY partition_expression [, ...] ]
  [ ORDER BY expression [ { ASC | DESC }  ] [, ...] ]
  [ window_frame_clause ]

Description

Returns the sample (unbiased) variance of the values. The return result is between 0 and +Inf.

All numeric types are supported. If the input is NUMERIC or BIGNUMERIC then the internal aggregation is stable with the final output converted to a FLOAT64. Otherwise the input is converted to a FLOAT64 before aggregation, resulting in a potentially unstable result.

This function ignores any NULL inputs. If there are fewer than two non-NULL inputs, this function returns NULL.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

To learn more about the OVER clause and how to use it, see Window function calls.

Return Data Type

FLOAT64

VARIANCE

VARIANCE(
  [ DISTINCT ]
  expression
)
[ OVER over_clause ]

over_clause:
  { named_window | ( [ window_specification ] ) }

window_specification:
  [ named_window ]
  [ PARTITION BY partition_expression [, ...] ]
  [ ORDER BY expression [ { ASC | DESC }  ] [, ...] ]
  [ window_frame_clause ]

Description

An alias of VAR_SAMP.