Sql server 如何使用SQL从表列中仅检索小于给定值的值

如果余额小于500，我必须对只返回行进行查询。但是仍然得到了SQL表的所有行

我的问题是：

SELECT  
    a.[ID], a.[strUserName],
    (SELECT intCurrentBalance 
     FROM accountmappings 
     WHERE intUserID = a.[ID] AND intAccountType = 1 
       AND (intCurrentBalance < 500 AND intCurrentBalance IS NOT NULL)) AS Prm_Balance,
    (SELECT intCurrentBalance 
     FROM accountmappings 
     WHERE intUserID = a.[ID] AND intAccountType = 2 
       AND (intCurrentBalance < 500 AND intCurrentBalance IS NOT NULL)) AS Trn_Balance,
    (SELECT intCurrentBalance 
     FROM accountmappings 
     WHERE intUserID = a.[ID] AND intAccountType = 3 
       AND (intCurrentBalance < 500 AND intCurrentBalance IS NOT NULL)) AS Opt_Balance,
    a.[strMobile],
    a.[strEmailID], 
    a.[bIsApproved],
    a.[bIsActive],
    a.[dtlastrecharge],
    CASE WHEN b.id IS NULL THEN 0 ELSE b.id END AS createdbyId,
    CASE WHEN b.strusername IS NULL THEN '' ELSE b.strusername END AS createdby
FROM 
    users a 
LEFT JOIN
    users b ON a.intCreatedBy = b.ID

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您的查询应该返回它没有where子句的所有行。只有相关子查询检查余额是否小于500。如果找不到合适的值，这些子查询将返回NULL。提示：在子查询中使用表别名，并将其应用于所有列引用。@HABO-你能用一些代码解释一下吗…我不明白什么是CB…@shalingajjar CB是intCurrentBalance表的对象

SELECT  a.[ID] ,a.[strUserName],
             (CASE WHEN CB.intAccountType = 1 THEN CB.intCurrentBalance else 0) as Prm_Balance
            ,(CASE WHEN CB.intAccountType = 2 THEN CB.intCurrentBalance else 0) as Trn_Balance
            ,(CASE WHEN CB.intAccountType = 3 THEN CB.intCurrentBalance else 0) as Opt_Balance
            ,a.[strMobile]
            ,a.[strEmailID]
            ,a.[bIsApproved]
            ,a.[bIsActive]
            ,a.[dtlastrecharge]
            ,case when b.id is null then 0 else b.id end as createdbyId
            ,case when b.strusername is null then '' else b.strusername end as createdby
             FROM users a 
             left join users b on a.intCreatedBy = b.ID
             inner join intCurrentBalance CB on intUserID = a.[ID] and (CB.intCurrentBalance IS NOT NULL and CB.intCurrentBalance < 500)