Tarantool Aggregation Query

Tarantool is a high-performance open source In-memory database, which provides rich aggregate query functions. Below are some commonly used aggregation queries and sample implementations supported by Tarantool. 1. COUNT aggregate query: used to count the number of records that match a certain condition. Example: Suppose there is a table named users that contains the following fields: |Id | name | age| |----|-------|-----| |1 | Alice | 25| |2 | Bob | 30| |3 | Carol | 40| Number of records with Bob as the name field in the statistical table: lua local count = box.space.users.index.name:count("Bob") 2. SUM aggregation query: used to calculate the total of a certain field. Example: Calculate the total of age fields in the table: lua local sum = box.space.users:select():sum(function(tuple) return tuple.age end) 3. AVG aggregation query: used to calculate the average value of a certain field. Example: Calculate the average value of the age field in the table: lua local avg = box.space.users:select():avg(function(tuple) return tuple.age end) 4. MIN and MAX aggregate queries: used to find the minimum and maximum values of a certain field. Example: Find the minimum and maximum values for the age field in the table: lua local min_age = box.space.users:select():min(function(tuple) return tuple.age end) local max_age = box.space.users:select():max(function(tuple) return tuple.age end) 5. GROUP BY and HAVING aggregate queries: used to group by a certain field and perform conditional filtering. Example: Group according to the age field and only return records with an age greater than or equal to 30: lua local result = box.space.users:select():group_by("age"):having("age >= 30"):exec() 6. DISTINCT aggregate query: used to return deduplication results for specific fields. Example: Return the deduplication result of the name field: lua local result = box.space.users.index.name:select({}, {distinct = true}) These are some commonly used aggregation queries supported by Tarantool, and appropriate aggregation query methods can be selected based on specific needs. In the example, suppose there is a table named users that contains id, name, and age fields.