[{"_id":ObjectId("626f942bb092f78afd9dad9c"),"item_id":"external _id222","metadata":{"item_name":"abc","quantity":122,"state":null}},{"_id":ObjectId("626f942bb092f78afd9dad9d"),"item_id":"external _id222","metadata":{"item_name":"abc","quantity":123,"state":null}},{"_id":ObjectId("626f942bb092f78afd9dad9e"),"item_id":"external _id222","metadata":{"item_name":"abc","quantity":124,"state":null}},{"_id":ObjectId("626f942bb092f78afd9dad9f"),"item_id":"external _id222","metadata":{"item_name":"abc","quantity":125,"state":null}}]

db.collection.update({"item_id":"external _id222"},[{$set:{"metadata.quantity":{$add:["$metadata.quantity",1]}}},{$set:{"metadata.state":{$cond:{if:{$eq:["$metadata.quantity",124]},then:"SOLID",else:"$metadata.state"}}}}],{multi:true})