In MongoDB, the $mergeObjects aggregation pipeline operator combines multiple documents into a single document.
Tag: aggregation
MongoDB $isArray
In MongoDB you can use the $isArray aggregation pipeline operator to check whether or not a value is an array.
It accepts any valid expression, and returns true if the expression is an array, false if it’s not.
MongoDB $literal
In MongoDB, the $literal aggregation pipeline operator returns a value without parsing.
It accepts any valid expression, and returns the unparsed expression.
The $literal operator can be useful for when you have a value that MongoDB could inadvertently interpret as an expression, but you don’t want it to.
For example, if you have a monetary amount that includes a dollar sign, MongoDB might inadvertently interpret that as a field name. You can use $literal to prevent MongoDB from interpreting such expressions.
MongoDB $ln
In MongoDB, the $ln aggregation pipeline operator calculates the natural logarithm (ln) of a number and returns the result as a double.
MongoDB $log
In MongoDB, the $log aggregation pipeline operator calculates the log of a number in the specified base and returns the result as a double.
MongoDB $indexOfCP
In MongoDB, the $indexOfCP aggregation pipeline operator searches a string for an occurrence of a substring and returns the UTF code point index of the first occurrence.
The UTF code point index is zero-based (i.e. it starts at 0).
MongoDB $indexOfBytes
In MongoDB, the $indexOfBytes aggregation pipeline operator searches a string for an occurrence of a substring and returns the UTF-8 byte index of the first occurrence.
The UTF byte index is zero-based (i.e. it starts at 0).
MongoDB $indexOfArray
In MongoDB, the $indexOfArray aggregation pipeline operator searches an array for an occurrence of a specified value and returns the array index of the first occurrence.
MongoDB $trunc
In MongoDB, the $trunc aggregation pipeline operator truncates a number to a whole integer or to a specified decimal place.
You have the option of specifying how many decimal places for which to truncate the number. To do this, pass a second argument. The first argument is the number to truncate, and the second (optional) argument is the number of decimal places to truncate it to.
Omitting the second argument truncates all digits to the right of the decimal and returns the whole integer value.
Continue readingMongoDB $or Aggregation Pipeline Operator
In MongoDB, the $or aggregation pipeline operator evaluates one or more expressions and returns true if any evaluate to true. Otherwise it returns false.