prev()

Returns the value of a column in a row that it at some offset prior to the current row in a serialized row set.

Syntax

prev(column)

prev(column, offset)

prev(column, offset, default_value)

Arguments

  • column: the column to get the values from.

  • offset: the offset to go back in rows. When no offset is specified a default offset 1 is used.

  • default_value: the default value to be used when there is no previous rows to take the value from. When no default value is specified, null is used.

Examples

Table | serialize | extend prevA = prev(A,1)
| extend diff = A - prevA
| where diff > 1

Table | serialize prevA = prev(A,1,10)
| extend diff = A - prevA
| where diff <= 10