Question

我对SQL很陌生，但鉴于以下示例，有没有办法压缩查询？根据我的理解，SQL没有数组，但是可以以某种方式存储表并执行一个SELECT语句，可能是一个变量（从Table_Name中选择Count（*））作为Table_Name）？

SELECT
(SELECT COUNT(*) FROM ActivityLog) AS ActivityLog,
(SELECT COUNT(*) FROM ActivityLogin) AS ActivityLogin,
(SELECT COUNT(*) FROM ActivityPlayContent) AS ActivityPlayContent,
(SELECT COUNT(*) FROM ChangeLog) AS ChangeLog,
(SELECT COUNT(*) FROM ContentApprovalLog) AS ContentApprovalLog,
(SELECT COUNT(*) FROM ExceptionLog) AS ExceptionLog,
(SELECT COUNT(*) FROM State) AS State

Answer 1

如果您经常需要此查询并希望更简单，则可以创建VIEW。然后，您必须像查询表一样查询视图。

SELECT * FROM MyView

当您有多个复杂查询并希望在其他查询中重复使用它们时，视图尤其有用（例如，将两个视图连接在一起或子视图中）。

为您的查询创建视图，如下所示

CREATE VIEW MyView AS
SELECT
(SELECT COUNT(*) FROM ActivityLog) AS ActivityLog,
(SELECT COUNT(*) FROM ActivityLogin) AS ActivityLogin,
(SELECT COUNT(*) FROM ActivityPlayContent) AS ActivityPlayContent,
(SELECT COUNT(*) FROM ChangeLog) AS ChangeLog,
(SELECT COUNT(*) FROM ContentApprovalLog) AS ContentApprovalLog,
(SELECT COUNT(*) FROM ExceptionLog) AS ExceptionLog,
(SELECT COUNT(*) FROM State) AS State

使用变量使用一个SELECT语句对多个表进行SQL查询

1 个答案: