How Can I increment some number field (but String) with a specific condition in Mongodb?

Question

Hi Everyone of StackOverflow Community,

I have a doubt in an activity that I have to do for homework.

I want to know how I can increment one field in every document that is filtered by a specific condition. My problem is not in the update code, in termes that this number field to increment was a number type (int, float, double,...), but yes when I have to increment that field values (numbers) in a field that has String as a field type.

It give my that error (ScreenShot):

ERROR MongoDB Update

Thanks.

See you,

As you've found, you can't use `$inc` with string values. Can you update your question with a specific example of what you're trying to do? — JohnnyHK, Apr 16 '19 at 00:09
JohnnyHK, what I'm trying to do with $Inc is to sum 5 to a a field that has String as type — Oriol Cantarell Sala, Apr 16 '19 at 00:15
You can't do that in a single update; you'd have to find the document, convert the string to number, add 5, convert it back to a string, and update the document with `$set`. — JohnnyHK, Apr 16 '19 at 00:25

score 0 · Accepted Answer · edited Apr 20 '19 at 01:32

0

One way to solve it is like JohnnyHK said in the comment:

You can't do that in a single update; you'd have to find the document, convert the string to number, add 5, convert it back to a string, and update the document with $set.

Another possibility is found in the following question:

how to convert string to numerical values in mongodb

edited Apr 20 '19 at 01:32

Wai Ha Lee

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answered Apr 19 '19 at 23:44

Oriol Cantarell Sala

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Ok Wai Ha Lee (I know to put the link as a unorganized list with 1item) and I also know ho to make a cite to a comment (I didn't do because I thought it was intuitive) , but how did you put the mention to JohnnyHK? (typing its user profile URL?) – Oriol Cantarell Sala Apr 20 '19 at 18:44
Thanks. [Wai Ha Lee](https://stackoverflow.com/users/1364007/wai-ha-lee) !! – Oriol Cantarell Sala Apr 20 '19 at 22:53

How Can I increment some number field (but String) with a specific condition in Mongodb?

1 Answers1