May 20, 2021 WeChat Mini Program Development Document
Database aggregation operator, obtained from db.command.aggregate
The aggregate operator. Returns the absolute value of a number.
The aggregate operator. A dd numbers or add numbers to the date. If one of the values in the array is a date, the other values are treated as milliseconds added to that date.
The aggregate operator. T he aggregation operator. A dd a value to the array and do nothing if it already exists in the array. It can only be used in group stage.
The aggregate operator. E nter an array, or an expression for an array field. I f all elements in the array are true, true is returned, otherwise false is returned. The empty array returns true forever.
The aggregate operator. Given multiple expressions, and returns true only when all expressions return true, otherwise false is returned.
The aggregate operator.Enter an array, or an expression of array fields.If any element in the array is true, then returns true, otherwise returns false.Empty array always returns false.
The aggregate operator.Returns the elements marked in the specified array.
The aggregate operator.Convert an array to an object.
The aggregate operator.Returns a set of sets, specify the average of the fields corresponding to the field.
The aggregate operator.Top up, return to the minimum integer greater than or equal to a given number.
The aggregate operator.Given two values, returns to their comparison values:
The aggregate operator.Connect the string, return the string after stitching.
The aggregate operator.Multiple arrays into an array.
The aggregate operator.Calculate Boolean expressions and return one of the specified two values.
The aggregate operator.Related information about a given date, build and return a date object.
The aggregate operator.Convert a date / time string into a date object
The aggregate operator.Format the date object as a string that meets the requirements based on the specified expression.
The aggregate operator.Returns the number of days corresponding to the date field (which day in a month) is a number between 1 to 31.
The aggregate operator. Returns the number of days (the day of the week) corresponding to the date field, which is an integer between 1 (Sunday) and 7 (Saturday).
The aggregate operator. Returns the number of days (the first day of the year) for the date field, which is an integer between 1 and 366.
The aggregate operator. Incoming dividers and divides, asking for business.
The aggregate operator. Match two values and return true if equal, otherwise false is returned.
The aggregate operator. Take the nth square of e (the bottom of the natural pair, the Eurass).
The aggregate operator. Returns a subset of arrays that meet the criteria based on a given condition.
The aggregate operator. R eturns the value that corresponds to the first record of the specified field in a set of collections. This action makes sense only if the collection is sorted by some definition.
The aggregate operator. Round down to return a minimum integer that is greater than or equal to a given number.
The aggregate operator. Match two values, and return true if the former is greater than the latter, otherwise false is returned.
The aggregate operator. Match two values, and if the former is greater than or equal to the latter, true is returned, otherwise false is returned.
The aggregate operator. The number of hours corresponding to the return date field is an integer between 0 and 23.
The aggregate operator. Evaluates a given expression and returns an alternative value if the expression results in null, undefined, or does not exist;
The aggregate operator. Given a value and an array, if the value is in the array, true is returned, otherwise false is returned.
The aggregate operator. Find the lower sign of the first element equal to a given value in the array and return -1 if not found.
The aggregate operator. L ook for substrings in the target string and return the byte index of UTF-8 that first appears, starting at 0. If a substring does not exist, return -1.
The aggregate operator. L ook for substrings in the target string and return the code point index of UTF-8, which first appears, starting at 0. If a substring does not exist, return -1.
The aggregate operator. Determines whether a given expression is an array and returns a Boolean value.
The aggregate operator. Returns the number of days of the ISO 8601 standard (the day of the week) corresponding to the date field, which is an integer between 1 (Monday) and 7 (Sunday).
The aggregate operator. Returns the number of weeks of the ISO 8601 standard (the first few weeks of the year) corresponding to the date field, which is an integer between 1 and 53.
The aggregate operator. Returns the number of days (the first day of the year) corresponding to the ISO 8601 standard for the date field.
The aggregate operator. R eturns the value of the specified field for the last record in a set of collections. This action makes sense only if the collection is sorted by some definition.
The aggregate operator. Custom variables, and used in the specified expression, return the result of the expression.
The aggregate operator. Returns a literal amount of a value directly without any resolution and processing.
The aggregate operator. Calculates a given number in a natural pair of values.
The aggregate operator. Calculates the log value of a given number at the bottom of a given log log.
The aggregate operator. Calculates the log value of a given number at the bottom of the log at the bottom of the log.
The aggregate operator. Match two values, and return true if the former is less than the latter, otherwise false is returned.
The aggregate operator. Match two values, and return true if the former is less than or equal to the latter, otherwise false is returned.
The aggregate operator. Similar to the map method on JavaScript Array, each element of a given array is converted to a new array by a given conversion method.
The aggregate operator. Returns the maximum value for a set of values.
The aggregate operator. Combine multiple documents into a single document.
The aggregate operator. Returns the number of milliseconds corresponding to the date field, which is an integer between 0 and 999.
The aggregate operator. Returns the minimum value of a set of values.
The aggregate operator. The number of minutes corresponding to the return date field is an integer between 0 and 59.
The aggregate operator. The molding operation, taking the value after the digital molding.
The aggregate operator. Returns the month corresponding to the date field, which is an integer between 1 and 12.
The aggregate operator. Take the result of multiplying the incoming numeric parameters.
The aggregate operator. Match two values and return true if they are not equal, otherwise false is returned.
The aggregate operator. G iven an expression, if the expression returns true, not returns false, otherwise true is returned. Note that expressions cannot be logical expressions (and, or, nor, not).
The aggregate operator. C onvert an object to an array. The method turns each pair of key values of an object into an element of the output array, which is shaped like .
The aggregate operator. Given multiple expressions, if any one expression returns true, or returns true, otherwise false is returned.
The aggregate operator. Find the exponential power of a given base.
The aggregate operator. During the group stage, an array of expressions in a set of expressions is returned that specifies that the columns are composed together with the corresponding values.
The aggregate operator. R eturns a set of generated sequence numbers. Given a start value, an end value, a non-zero step, the range returns a sequence that grows gradually from the start value to a given step, but does not include the end value.
The aggregate operator. The JavaScript-like reduce method applies an expression to each element of the array and then groups them into one element.
The aggregate operator. Returns the inverted form of a given array.
The aggregate operator. Returns the number of seconds corresponding to the date field, which is an integer between 0 and 59, and in exceptional cases (leap seconds) may be equal to 60.
The aggregate operator enters two collections, and the output exists only in the elements in the first collection.
Aggregate operators, enter two collections, and determine whether the elements contained in the two collections are the same (no order, de-weighting).
Aggregate operators, enter two collections, and output the intersection of two collections.
Aggregate operators, enter two collections, and determine whether the first collection is a subset of the second collection.
Aggregate operators, enter two collections, and output the contrase of two collections.
The aggregate operator. Returns the length of the array.
The aggregate operator. A slice method similar to JavaScritp. Returns a specified subset of a given array.
The aggregate operator. S eparate the array by separator, and remove the separator, returning an array of substrings. If the string cannot be separated by a separator, the original string is returned as the unique element of the array.
The aggregate operator. Find the square root.
The aggregate operator. Returns a set of fields that correspond to the standard deviation of the value.
The aggregate operator. C alculate the sample standard deviation for the input value. If the input value represents the data population, or does not summarize more data, use db.command.aggregate.stdDevPop between .
The aggregate operator. Calculates and returns the number of bytes encoded by utf-8 in the specified string.
The aggregate operator. Calculate and return the number of UTC-8 code points for the specified string.
The aggregate operator. Make a case-insensession-sensitive size comparison of the two strings and return the results of the comparison.
The aggregate operator. R eturns a substring of the specified length of the string starting at the specified location. It is an alias for db.command.aggregate.substrBytes and is more recommended.
The aggregate operator. R eturns a substring of the specified length of the string starting at the specified location. Substrings start with characters in the UTF-8 byte index specified in the string and are the number of bytes specified.
The aggregate operator. R eturns a substring of the specified length of the string starting at the specified location. Substrings start with characters in the UTF-8 byte index specified in the string and are the number of bytes specified.
The aggregate operator. Subtract two numbers and return the difference, or subtract the two dates and then return the difference of milliseconds, or subtract one date from the date on which a number returns the result.
The aggregate operator. Calculates and returns the sum of all the values in a set of fields.
The aggregate operator. The return value is calculated based on the given switch-case-default,
The aggregate operator. Convert the string into a small case and return it.
The aggregate operator. Convert the string to capital and return.
The aggregate operator. Truncated the number to shape.
The aggregate operator. Returns the number of weeks (the first few weeks of the year) for the date field, which is an integer between 0 and 53.
The aggregate operator. Returns the year for which the date field corresponds.
The aggregate operator. T he elements of the same serial number in the second-dimensional array of the two-dimensional array are assembled into a new array and then assembled into a new two-dimensional array. If you can convert the s.1, 2, 3, s.a", "b", "c" , s.