Master three of MongoDB's most useful and specific query operators! This tutorial shows you how to find documents based on field existence, data type, or text patterns.
What you will learn:
$exists (Element Operator): How to find documents that have a specific field ($exists: true), or are missing a specific field ($exists: false). This is perfect for data cleanup.
$type (Element Operator): How to query for documents where a field's value is a specific BSON data type (like "string", "double", "array", "bool", or "null").
$regex (Query Operator): How to perform powerful text searches (like SQL's "LIKE" operator). We'll show you how to find text that contains a string, starts with a string (^), and how to make your search case-insensitive using $options: 'i'.
Example ($exists): db.users.find({ email: { $exists: true } })
Example ($type): db.products.find({ price: { $type: "double" } })
Example ($regex): db.users.find({ username: { $regex: 'admin', $options: 'i' } })
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