Overview

Table 1 lists the window functions supported by DLI.

**Table 1** Window functions
Function	Syntax	Value Type	Description
cume_dist	cume_dist()	DOUBLE	Returns the cumulative distribution, which is equivalent to calculating the proportion of data in the partition that is greater than or equal to, or less than or equal to, the current row.
first_value	first_value(col)	Data type of the argument	Returns the value of the first data record in a column in a result set.
last_value	last_value(col)	Data type of the argument	Returns the value of the last data record from a column.
lag	lag (col,n,DEFAULT)	Data type of the argument	Returns the value from the nth row preceding the current row. The first argument specifies the column name. The second argument specifies the nth row preceding the current row. The configuration of the second argument is optional, and the default argument value is 1 if the argument is not specified. The third argument is set to a default value. If the nth row preceding the current row is null, the default value is used. The default value of the third argument is NULL if the argument is not specified.
lead	lead (col,n,DEFAULT)	Data type of the argument	Returns the value from the nth row following the current row. The first argument specifies the column name. The second argument specifies the nth row following the current row. The configuration of the second argument is optional, and the default argument value is 1 if the argument is not specified. The third argument is set to a default value. If the nth row following the current row is null, the default value is used. The default value of the third argument is NULL if the argument is not specified.
percent_rank	percent_rank()	DOUBLE	Returns the rank of a value from the column specified by the ORDER BY clause of the window. The return value is a decimal between 0 and 1, which is calculated using (RANK - 1)/(- 1).
rank	rank()	INT	Returns the rank of a value in a set of values. When multiple values share the same rank, the next rank in the sequence is not consecutive.
row_number	row_number() over (order by col_1[,col_2 ...])	INT	Assigns a unique number to each row.