Convert a Simple SQL SELECT to MongoDB find()

From SELECT to find()

The most fundamental conversion maps a SQL SELECT statement to MongoDB's db.collection.find() method. The first argument is the filter (empty {} for no conditions), and the second argument is the projection that controls which fields are returned.

Example SQL

SELECT name, email, age
FROM users

Generated MongoDB Query

db.users.find(
  {},
  {
    name: 1,
    email: 1,
    age: 1,
    _id: 0
  }
)

Key Mapping Rules

SQL Element	MongoDB Equivalent
SELECT col1, col2	Projection object with fields set to 1
SELECT *	No projection argument (all fields returned)
FROM table	db.table collection reference
Column exclusion	_id: 0 to suppress the default _id field

Projection Behavior

In MongoDB, a projection document uses 1 to include fields and 0 to exclude them. You cannot mix inclusion and exclusion in the same projection, with the sole exception of _id, which can always be explicitly excluded. When no projection is provided, all fields in the document are returned, equivalent to SELECT * in SQL.

Collection Naming

SQL table names map directly to MongoDB collection names. While SQL tables often use plural snake_case (user_accounts), MongoDB collections follow the same convention by default. The converter preserves the original table name as the collection name.