SQL Function Reference

LAG

Window function. Accesses data from previous rows of the window.

MySQL

LAG(column [, offset ] [, default])

column

Column whose value is to be returned

offset

Number of lines to offset (default 1)

default

The value to return if NULL is returned after the offset

Examples

MySQL

SELECT 
    member_name, 
    status, 
    LAG(member_name) OVER(ORDER BY status) AS 'lag_1',
    LAG(member_name, 2, 'empty') OVER(ORDER BY status) AS 'lag_2' 
    FROM FamilyMembers;