index_object:count()

object index_object¶

index_object:count([key][, iterator])¶

Iterate over an index, counting the number of tuples which match the key-value.

Parameters:	index_object (index_object) – an object reference. key (scalar/table) – values to be matched against the index key iterator – comparison method
Return:	the number of matching tuples.
Rtype:	number

Example:

Below are few examples of using count. To try out these examples, you need to bootstrap a Tarantool database as described in Using data operations.

-- Insert test data --
box.space.bands:insert { 1, 'Roxette', 1986 }
box.space.bands:insert { 2, 'Scorpions', 1965 }
box.space.bands:insert { 3, 'Ace of Base', 1987 }
box.space.bands:insert { 4, 'The Beatles', 1960 }
box.space.bands:insert { 5, 'Pink Floyd', 1965 }
box.space.bands:insert { 6, 'The Rolling Stones', 1962 }
box.space.bands:insert { 7, 'The Doors', 1965 }
box.space.bands:insert { 8, 'Nirvana', 1987 }
box.space.bands:insert { 9, 'Led Zeppelin', 1968 }
box.space.bands:insert { 10, 'Queen', 1970 }

-- Count the number of tuples that match the full key value
count = box.space.bands.index.year:count(1965)
--[[
---
- 3
...
--]]

-- Count the number of tuples that match the partial key value
count_partial = box.space.bands.index.year_band:count(1965)
--[[
---
- 3
...
--]]