Sql server 如何将此查询更改为使用联接（内部或左侧）而不是子查询来获得相同的结果

如何将此查询更改为使用联接（内部或左侧），而不使用子查询

 SELECT * FROM   External_Blk_Itm_Contracts ELC
    WHERE
    NOT EXISTS(SELECT
                    NULL
                FROM        
                    [BUDCONTRACTS] c
                INNER JOIN 
                    BUDTERMINALS t on t.TerminalID = c.TerminalID  AND  t.MBFTERMINALNAME = ELC.TerminalName AND  c.CONTRACTNAME = ELC.ContractName 
                INNER JOIN 
                    BudCustomers ct on ct.CustomerId = c.CustomerId AND ELC.CustomerName = ct.LegalName
               )
                AND ELC.ContractName = '00-000'

未经测试（显然）：

关于这一点，我最大的问题是为什么我们要使用名称字段加入ELC？ELC上没有TerminalID、CustomerID和CotractID等吗？

我通过

        SELECT ELC.* FROM External_Blk_Itm_Contracts ELC
        INNER JOIN BUDTERMINALS BT ON BT.MBFTERMINALNAME = ELC.TerminalName AND ELC.ContractName = '00-000' 
        INNER JOIN BudCustomers BCUST ON BCUST.LegalName = ELC.CustomerName
        LEFT JOIN BUDCONTRACTS BCON ON BCON.CONTRACTNAME = ELC.ContractName AND BCON.TERMINALID = BT.TERMINALID AND BCON.CUSTOMERID = BCUST.CustomerID  
        WHERE    BCON.CONTRACTID IS NULL

---

我认为它应该表现得更好，因为左连接会降低效率，我想涉及的表的模式是什么？特别是主键和外键列？你能发布一个吗？我希望相同的查询与不带子查询的连接@TabAlleman Not duplicate的可能重复项相同

        SELECT ELC.* FROM External_Blk_Itm_Contracts ELC
        INNER JOIN BUDTERMINALS BT ON BT.MBFTERMINALNAME = ELC.TerminalName AND ELC.ContractName = '00-000' 
        INNER JOIN BudCustomers BCUST ON BCUST.LegalName = ELC.CustomerName
        LEFT JOIN BUDCONTRACTS BCON ON BCON.CONTRACTNAME = ELC.ContractName AND BCON.TERMINALID = BT.TERMINALID AND BCON.CUSTOMERID = BCUST.CustomerID  
        WHERE    BCON.CONTRACTID IS NULL