SQLiteCustomAggregate

protocol SQLiteCustomAggregate : Sendable

Overview

For example:

struct MySum: DatabaseAggregate {
    var sum: Int = 0

    mutating func step(_ dbValues: [SQLiteData]) {
        if let int = dbValues[0].integer {
            sum += int
        }
    }

    func finalize() -> (any SQLiteDataConvertible)? {
        sum
    }
}

let connection: SQLiteConnection = ...
let fn = SQLiteCustomFunction("mysum", argumentCount: 1, aggregate: MySum.self)
try await connection.install(customFunction: fn).get()
try await connection.query("CREATE TABLE test(i)").get()
try await connection.query("INSERT INTO test(i) VALUES (1)").get()
try await connection.query("INSERT INTO test(i) VALUES (2)").get()
let sum = (try await connection.query("SELECT mysum(i) FROM test").get().first?.columns.first?.integer)!