I have 2 columns A and B, Data I have is daily from Feb to July.For Feb to march I dont have Column B. My Task is as follows
Task 1 : if Column B is not present create a column in document and copy A Column to B
Task 2: If column already exists leave it with data.
Tried so far: col.find({colb:{"$exisits:True", "$set"}})....
please guide me
You need to use MongoDB aggregation. The $ifNull operator is what you need.
db.collection.aggregate([
{
"$addFields": {
"colb": {
"$ifNull": [
"$colb",
"$cola"
]
}
}
}
])
With $project
db.collection.aggregate([
{
"$project": {
"cola": "$cola",
"colb": {
"$ifNull": [
"$colb",
"$cola"
]
}
}
}
])