合并行并给我总数

Question

我想计算一个用户玩过多少独特的游戏。以下是当前 SQL 查询的样子：

SELECT COUNT(DISTINCT d.id_game) AS c
FROM discord AS d
JOIN discord_games AS dg
ON d.id_game = dg.id
WHERE d.id_user = '1'
AND d.id_game != '0'
GROUP BY d.id_game
ORDER BY dg.data_name ASC

现在数据库看起来像这样：

CREATE TABLE IF NOT EXISTS `discord` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `id_user` int(11) NOT NULL,
  `id_channel` varchar(50) NOT NULL,
  `id_game` int(11) NOT NULL,
  `data_muted_server` tinyint(4) NOT NULL,
  `data_muted_self` tinyint(4) NOT NULL,
  `data_deafen_server` tinyint(4) NOT NULL,
  `data_deafen_self` tinyint(4) NOT NULL,
  `data_suppressed` tinyint(4) NOT NULL,
  `data_status` varchar(10) NOT NULL,
  `datetime_logged` datetime NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `id` (`id`)
)


CREATE TABLE IF NOT EXISTS `discord_games` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `data_name` varchar(50) NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `id` (`id`)
)


CREATE TABLE IF NOT EXISTS `discord_users` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `data_id` text NOT NULL,
  `data_name` varchar(50) NOT NULL,
  `data_avatar` text,
  PRIMARY KEY (`id`),
  UNIQUE KEY `id` (`id`)
)

SQL 查询计数正确，但每行仅计数 1。

我的想法示例。如果 ID 为 1 的用户玩过同一个游戏 24 次（例如战地 3），它将返回 1 个玩过的游戏。如果同一用户玩另一个游戏 37 次，它将返回 2 个玩过的游戏，依此类推。

SUM(DISTINCT ... 不起作用，因为它仅将 1 替换为游戏 ID。

如何对行求和以显示数字 2 而不是 2 行？

Answer 1

您可以按属性删除组并计算所玩的不同游戏。它将返回用户玩的不同游戏的数量 1

SELECT COUNT(DISTINCT d.id_game) AS c
FROM discord AS d
JOIN discord_games AS dg
ON d.id_game = dg.id
WHERE d.id_user = '1'
AND d.id_game != '0'
ORDER BY dg.data_name ASC