带有 COUNT 帮助的 SQL 子查询

Question

我有一个有效的 SQL 语句

SELECT * FROM eventsTable WHERE columnName='Business'

我想将其添加为子查询...

COUNT(Business) AS row_count

我该怎么做？

Answer 1

这可能是最简单的方法，但不是最漂亮的:

SELECT *,
    (SELECT Count(*) FROM eventsTable WHERE columnName = 'Business') as RowCount
    FROM eventsTable
    WHERE columnName = 'Business'

这也可以在不使用group by的情况下工作

SELECT *, COUNT(*) OVER () as RowCount
    FROM eventsTables
    WHERE columnName = 'Business'