MongoDB Query Language (MQL) Conditional Expression Operators
$cond
The `$cond` operator is used to evaluate a condition and return one of two expressions based on the result. It's similar to the ternary operator in many programming languages.
$ifNull
The `$ifNull` operator is used to evaluate an expression and return a specified value if the expression resolves to `null`.
$switch
The `$switch` operator is used to evaluate a series of conditions and return a value based on the first condition that evaluates to true.