Querying MongoDB with AND/OR Precedence

Question

Querying MongoDB with AND/OR Precedence

In MongoDB, when trying to express A AND (B OR C), it can easily be done with the following query:

db.demo.find( { a: 1, $or: [ {b:1}, {c:1} ] });

However, if the requirement is to have (A AND B) OR C -- this doesn't seem to work as expected. Using the query below:

db.demo.find( { $or: [ {a:1,b:1}, {c:1} ] });

The above query treats it as A or B or C, which is equivalent to:

db.demo.find( { $or: [ {a:1}, {b:1}, {c:1} ] });

Currently, I am avoiding using Javascript expression $where to achieve this because I am creating general filter rules directly converted into MongoDB queries.

Any suggestions or alternative methods?

javascript mongodb

Answer 1

Answer №1

The query is functioning correctly and serving its intended purpose. The issue lies in the wording of the question itself.

Below is a glimpse of my attempted solution and its successful execution!

Data:

> db.demo.find() 
{ "_id" : 1, "age" : 38, "mgmt" : "no", "salary" : 100 } 
{ "_id" : 2, "age" : 45, "salary" : 200, "mgmt" : "no" } 
{ "_id" : 3, "age" : 50, "salary" : 250, "mgmt" : "no" } 
{ "_id" : 4, "age" : 51, "salary" : 75, "mgmt" : "yes" } 
{ "_id" : 5, "age" : 45, "salary" : 75, "mgmt" : "no" }

Query to retrieve records where (Age > 40 AND Salary > 200) OR mgmt='yes'

> db.demo.find( { $or: [ { age: {$gt:40}, salary:{$gt:200} }, {mgmt: 'yes'} ] }) 
{ "_id" : 3, "age" : 50, "salary" : 250, "mgmt" : "no" } 
{ "_id" : 4, "age" : 51, "salary" : 75, "mgmt" : "yes" }

Query to retrieve records where Age > 40 OR Salary > 200 OR mgmt='yes'

> db.demo.find( { $or: [ { age: {$gt:40}}, {salary:{$gt:201} }, {mgmt: 'yes'} ] }) 
{ "_id" : 2, "age" : 45, "salary" : 200, "mgmt" : "no" } 
{ "_id" : 3, "age" : 50, "salary" : 250, "mgmt" : "no" } 
{ "_id" : 4, "age" : 51, "salary" : 75, "mgmt" : "yes" } 
{ "_id" : 5, "age" : 45, "salary" : 75, "mgmt" : "no" }

All queries are producing the expected results. Success!

Answer 2

The query is functioning correctly and serving its intended purpose. The issue lies in the wording of the question itself.

Below is a glimpse of my attempted solution and its successful execution!

Data:

> db.demo.find() 
{ "_id" : 1, "age" : 38, "mgmt" : "no", "salary" : 100 } 
{ "_id" : 2, "age" : 45, "salary" : 200, "mgmt" : "no" } 
{ "_id" : 3, "age" : 50, "salary" : 250, "mgmt" : "no" } 
{ "_id" : 4, "age" : 51, "salary" : 75, "mgmt" : "yes" } 
{ "_id" : 5, "age" : 45, "salary" : 75, "mgmt" : "no" }

Query to retrieve records where (Age > 40 AND Salary > 200) OR mgmt='yes'

> db.demo.find( { $or: [ { age: {$gt:40}, salary:{$gt:200} }, {mgmt: 'yes'} ] }) 
{ "_id" : 3, "age" : 50, "salary" : 250, "mgmt" : "no" } 
{ "_id" : 4, "age" : 51, "salary" : 75, "mgmt" : "yes" }

Query to retrieve records where Age > 40 OR Salary > 200 OR mgmt='yes'

> db.demo.find( { $or: [ { age: {$gt:40}}, {salary:{$gt:201} }, {mgmt: 'yes'} ] }) 
{ "_id" : 2, "age" : 45, "salary" : 200, "mgmt" : "no" } 
{ "_id" : 3, "age" : 50, "salary" : 250, "mgmt" : "no" } 
{ "_id" : 4, "age" : 51, "salary" : 75, "mgmt" : "yes" } 
{ "_id" : 5, "age" : 45, "salary" : 75, "mgmt" : "no" }

All queries are producing the expected results. Success!

Querying MongoDB with AND/OR Precedence

Answer №1

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