php - 在单个查询中从一个表中选择 SUM+COUNT 并从另一个表中选择 COUNT

Question

我想从 users 表中获取年龄总和和活跃用户总数，以及从 pictures 表中获取 png 图片总数。我尝试了以下但它给了我错误。我如何在单个查询中执行此操作？我正在使用 PDO

SELECT
(SELECT SUM(age) AS age_sum,COUNT(*) AS total FROM users where type='active'),
(SELECT COUNT(*) AS pictotal FROM pictures where extension='png')

错误 -> 操作数应包含 1 列

Answer 1

选择
AA.age_sum，AA。总计，BB.pictotal
来自
(SELECT SUM(age) AS age_sum,COUNT(*) AS total FROM users where type='active') AA,
(SELECT COUNT(*) AS pictotal FROM pictures where extension='png') BB