简化MS SQL语句

Question

我读了一篇关于JOINS的好文章,"INNER JOIN"和"OUTER JOIN"有什么区别？但我不认为这有助于我的问题.

我想将两个select语句组合成一个select语句AND,使其对任何要查询的数据库都有效.

这就是我所拥有的

SELECT
(SELECT COUNT(*) 
                        FROM dbo.sem_computer, [dbo].[V_SEM_COMPUTER], dbo.IDENTITY_MAP, dbo.SEM_CLIENT,dbo.SEM_AGENT,dbo.PATTERN
                        WHERE [dbo].[V_SEM_COMPUTER].COMPUTER_ID = SEM_COMPUTER.COMPUTER_ID
                        AND dbo.SEM_CLIENT.GROUP_ID = IDENTITY_MAP.ID
                        AND dbo.SEM_CLIENT.COMPUTER_ID = SEM_COMPUTER.COMPUTER_ID
                        AND SEM_COMPUTER.COMPUTER_ID = dbo.SEM_AGENT.COMPUTER_ID
                        AND dbo.PATTERN.PATTERN_IDX = dbo.SEM_AGENT.PATTERN_IDX
                        AND Name like '%Staten Island%'
                        AND dbo.SEM_AGENT.AGENT_VERSION LIKE '11.%'
                        AND dbo.SEM_COMPUTER.OPERATION_SYSTEM LIKE 'Windows%') AS 'Windows-SEP-11',
(SELECT COUNT(*) 
                        FROM dbo.sem_computer, [dbo].[V_SEM_COMPUTER], dbo.IDENTITY_MAP, dbo.SEM_CLIENT,dbo.SEM_AGENT,dbo.PATTERN
                        WHERE [dbo].[V_SEM_COMPUTER].COMPUTER_ID = SEM_COMPUTER.COMPUTER_ID
                        AND dbo.SEM_CLIENT.GROUP_ID = IDENTITY_MAP.ID
                        AND dbo.SEM_CLIENT.COMPUTER_ID = SEM_COMPUTER.COMPUTER_ID
                        AND SEM_COMPUTER.COMPUTER_ID = dbo.SEM_AGENT.COMPUTER_ID
                        AND dbo.PATTERN.PATTERN_IDX = dbo.SEM_AGENT.PATTERN_IDX
                        AND Name like '%Staten Island%'
                        AND dbo.SEM_AGENT.AGENT_VERSION LIKE '12.%'
                        AND dbo.SEM_COMPUTER.OPERATION_SYSTEM LIKE 'Windows%') AS 'Windows-SEP-12',
(SELECT COUNT(*) 
                        FROM dbo.sem_computer, [dbo].[V_SEM_COMPUTER], dbo.IDENTITY_MAP, dbo.SEM_CLIENT,dbo.SEM_AGENT,dbo.PATTERN
                        WHERE [dbo].[V_SEM_COMPUTER].COMPUTER_ID = SEM_COMPUTER.COMPUTER_ID
                        AND dbo.SEM_CLIENT.GROUP_ID = IDENTITY_MAP.ID
                        AND dbo.SEM_CLIENT.COMPUTER_ID = SEM_COMPUTER.COMPUTER_ID
                        AND SEM_COMPUTER.COMPUTER_ID = dbo.SEM_AGENT.COMPUTER_ID
                        AND dbo.PATTERN.PATTERN_IDX = dbo.SEM_AGENT.PATTERN_IDX
                        AND Name like '%Staten Island%'
                        AND dbo.SEM_AGENT.AGENT_VERSION LIKE '11.%'
                        AND dbo.SEM_COMPUTER.OPERATION_SYSTEM LIKE 'Mac%') AS 'Mac-SEP-11',
(SELECT COUNT(*)
                        FROM dbo.sem_computer, [dbo].[V_SEM_COMPUTER], dbo.IDENTITY_MAP, dbo.SEM_CLIENT,dbo.SEM_AGENT,dbo.PATTERN
                        WHERE [dbo].[V_SEM_COMPUTER].COMPUTER_ID = SEM_COMPUTER.COMPUTER_ID
                        AND dbo.SEM_CLIENT.GROUP_ID = IDENTITY_MAP.ID
                        AND dbo.SEM_CLIENT.COMPUTER_ID = SEM_COMPUTER.COMPUTER_ID
                        AND SEM_COMPUTER.COMPUTER_ID = dbo.SEM_AGENT.COMPUTER_ID
                        AND dbo.PATTERN.PATTERN_IDX = dbo.SEM_AGENT.PATTERN_IDX
                        AND Name like '%Staten Island%'
                        AND dbo.SEM_AGENT.AGENT_VERSION LIKE '12.%'
                        AND dbo.SEM_COMPUTER.OPERATION_SYSTEM LIKE 'Mac%')  AS 'Mac-SEP-12'

如何收缩这个SQL语句？即使我使用内部联接(我正在处理),这个语句是处理器密集型的(更不用说它看起来真的很低效)

Answer 1

你可以使用Conditional Aggregate.

还使用正确的INNER JOIN语法来连接两个表而不是旧式逗号分隔连接.将过滤器保留在Where子句中

SELECT Count(CASE
               WHEN dbo.SEM_AGENT.AGENT_VERSION LIKE '11.%'
                    AND dbo.SEM_COMPUTER.OPERATION_SYSTEM LIKE 'Windows%' THEN 1
             END) AS 'Windows-SEP-11',
       Count(CASE
               WHEN dbo.SEM_AGENT.AGENT_VERSION LIKE '12.%'
                    AND dbo.SEM_COMPUTER.OPERATION_SYSTEM LIKE 'Windows%' THEN 1
             END) AS 'Windows-SEP-12',
       Count(CASE
               WHEN dbo.SEM_AGENT.AGENT_VERSION LIKE '11.%'
                    AND dbo.SEM_COMPUTER.OPERATION_SYSTEM LIKE 'Mac%' THEN 1
             END) AS 'Mac-SEP-11',
       Count(CASE
               WHEN dbo.SEM_AGENT.AGENT_VERSION LIKE '12.%'
                    AND dbo.SEM_COMPUTER.OPERATION_SYSTEM LIKE 'Mac%' THEN 1
             END) AS 'Mac-SEP-12'
FROM   dbo.sem_computer
       INNER JOIN [dbo].[V_SEM_COMPUTER]
               ON [dbo].[V_SEM_COMPUTER].COMPUTER_ID = SEM_COMPUTER.COMPUTER_ID
       INNER JOIN dbo.SEM_AGENT
               ON SEM_COMPUTER.COMPUTER_ID = dbo.SEM_AGENT.COMPUTER_ID
       INNER JOIN dbo.SEM_CLIENT
               ON dbo.SEM_CLIENT.COMPUTER_ID = SEM_COMPUTER.COMPUTER_ID
       INNER JOIN dbo.IDENTITY_MAP
               ON dbo.SEM_CLIENT.GROUP_ID = IDENTITY_MAP.ID
       INNER JOIN dbo.PATTERN
               ON dbo.PATTERN.PATTERN_IDX = dbo.SEM_AGENT.PATTERN_IDX
WHERE  Name LIKE '%Staten Island%'