update query tutorial

techfort · Jun 29, 2020 · fabe503 · fabe503
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commit fabe503
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diff --git a/tutorials/Query Examples.md b/tutorials/Query Examples.md
@@ -319,6 +319,15 @@ var results = coll.find({
 });
 ```
 
+**$$eq, $$eq, etc.** - many filters support column comparisons - comparing one column in a document
+with another (instead of between column and value):
+```javascript
+// fetch documents where foo > bar
+var results = coll.find({{ foo: { $$gt: 'bar' } }})
+
+// instead of passing second column name, you can pass a function that computes value to compare against
+var results = coll.find({{ foo: { $$lt: doc => doc.bar + 1 } }})
+```
 ### Features which support 'find' queries
 These operators can be used to compose find filter objects which can be used within : 
 * Collection find()