Aggregate Functions¶
Aggregate functions operate on a set of values to compute a single result.
General¶
avg¶
Returns the average of numeric values in the specified column.
avg(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
Aliases¶
mean
bit_and¶
Computes the bitwise AND of all non-null input values.
bit_and(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
bit_or¶
Computes the bitwise OR of all non-null input values.
bit_or(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
bit_xor¶
Computes the bitwise exclusive OR of all non-null input values.
bit_xor(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
bool_and¶
Returns true if all non-null input values are true, otherwise false.
bool_and(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
bool_or¶
Returns true if any non-null input value is true, otherwise false.
bool_or(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
count¶
Returns the number of non-null values in the specified column.
To include null values in the total count, use count(*).
count(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
max¶
Returns the maximum value in the specified column.
max(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
mean¶
Alias of avg.
median¶
Returns the median value in the specified column.
median(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
min¶
Returns the minimum value in the specified column.
min(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
sum¶
Returns the sum of all values in the specified column.
sum(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
array_agg¶
Returns an array created from the expression elements. If ordering requirement is given, elements are inserted in the order of required ordering.
array_agg(expression [ORDER BY expression])
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
first_value¶
Returns the first element in an aggregation group according to the requested ordering. If no ordering is given, returns an arbitrary element from the group.
first_value(expression [ORDER BY expression])
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
last_value¶
Returns the last element in an aggregation group according to the requested ordering. If no ordering is given, returns an arbitrary element from the group.
last_value(expression [ORDER BY expression])
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
Statistical¶
corr¶
Returns the coefficient of correlation between two numeric values.
corr(expression1, expression2)
Arguments¶
expression1: First expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
expression2: Second expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
covar¶
Returns the covariance of a set of number pairs.
covar(expression1, expression2)
Arguments¶
expression1: First expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
expression2: Second expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
covar_pop¶
Returns the population covariance of a set of number pairs.
covar_pop(expression1, expression2)
Arguments¶
expression1: First expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
expression2: Second expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
covar_samp¶
Returns the sample covariance of a set of number pairs.
covar_samp(expression1, expression2)
Arguments¶
expression1: First expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
expression2: Second expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
stddev¶
Returns the standard deviation of a set of numbers.
stddev(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
stddev_pop¶
Returns the population standard deviation of a set of numbers.
stddev_pop(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
stddev_samp¶
Returns the sample standard deviation of a set of numbers.
stddev_samp(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
var¶
Returns the statistical variance of a set of numbers.
var(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
var_pop¶
Returns the statistical population variance of a set of numbers.
var_pop(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
var_samp¶
Returns the statistical sample variance of a set of numbers.
var_samp(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_slope¶
Returns the slope of the linear regression line for non-null pairs in aggregate columns. Given input column Y and X: regr_slope(Y, X) returns the slope (k in Y = k*X + b) using minimal RSS fitting.
regr_slope(expression1, expression2)
Arguments¶
expression_y: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
expression_x: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_avgx¶
Computes the average of the independent variable (input) expression_x for the non-null paired data points.
regr_avgx(expression_y, expression_x)
Arguments¶
expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_avgy¶
Computes the average of the dependent variable (output) expression_y for the non-null paired data points.
regr_avgy(expression_y, expression_x)
Arguments¶
expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_count¶
Counts the number of non-null paired data points.
regr_count(expression_y, expression_x)
Arguments¶
expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_intercept¶
Computes the y-intercept of the linear regression line. For the equation (y = kx + b), this function returns b.
regr_intercept(expression_y, expression_x)
Arguments¶
expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_r2¶
Computes the square of the correlation coefficient between the independent and dependent variables.
regr_r2(expression_y, expression_x)
Arguments¶
expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_sxx¶
Computes the sum of squares of the independent variable.
regr_sxx(expression_y, expression_x)
Arguments¶
expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_syy¶
Computes the sum of squares of the dependent variable.
regr_syy(expression_y, expression_x)
Arguments¶
expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_sxy¶
Computes the sum of products of paired data points.
regr_sxy(expression_y, expression_x)
Arguments¶
expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
Approximate¶
approx_distinct¶
Returns the approximate number of distinct input values calculated using the HyperLogLog algorithm.
approx_distinct(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
approx_median¶
Returns the approximate median (50th percentile) of input values.
It is an alias of approx_percentile_cont(x, 0.5).
approx_median(expression)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
approx_percentile_cont¶
Returns the approximate percentile of input values using the t-digest algorithm.
approx_percentile_cont(expression, percentile, centroids)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
percentile: Percentile to compute. Must be a float value between 0 and 1 (inclusive).
centroids: Number of centroids to use in the t-digest algorithm. Default is 100.
If there are this number or fewer unique values, you can expect an exact result. A higher number of centroids results in a more accurate approximation, but requires more memory to compute.
approx_percentile_cont_with_weight¶
Returns the weighted approximate percentile of input values using the t-digest algorithm.
approx_percentile_cont_with_weight(expression, weight, percentile)
Arguments¶
expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
weight: Expression to use as weight. Can be a constant, column, or function, and any combination of arithmetic operators.
percentile: Percentile to compute. Must be a float value between 0 and 1 (inclusive).