SQL code for last date of appearence por each month listing all months

I have a list of deliveries of each month and i want to know for each month how many months has passed since the last delivery for each client.

for example seeing client 1

client month deliveries
1. 1 202101 2
1. 1 202102 0
1. 1 202103 1
1. 1 202104 0
1. 1 202105 0
1. 1 202106 1

the output of what i expect is the following table

client analisys_month months_since_last_delivery
1. 1 202101. 0
1. 1 202102. 1
1. 1 202103. 0
1. 1 202104. 1
1. 1 202105. 2
1. 1 202106. 0

my question is to make 1 query that can solve the variable months_since_last_delivery for each one f 36 months of performances whitout making union for 36 different querys one for each month

Big Data Previous post Big Data vs. Hadoop
Application Programming Interfaces Next post An Outlook on Application Programming Interfaces