Question

我有以下查询需要几秒钟才能运行：

 SELECT COUNT(*) cnt
   FROM [PTYCHRG] A, [AVAIL_ACTION_TYPE_CODES_TEMP] B
  WHERE TRIM(A.CASE_ID) = TRIM(caseid)
    AND TRIM(B.casecode) = TRIM(casecd)
    AND (
            TRIM(A.ACTN_CD) = TRIM(B.ACTIONCODE)
            OR TRIM(A.INDICTED_ACTN_CD) = TRIM(B.ACTIONCODE)
            OR TRIM(A.AMENDED_ACTN_CD) = TRIM(B.ACTIONCODE)
        )
    AND LOWER(TRIM(B.DOMAIN)) = LOWER(TRIM(domain))
    AND [rownum] = 1;

我正在寻找一种方法/方法来加速它，因为它是更大过程的一部分。

我基本上想看看是否至少有一条记录（我不关心我撤回哪个字段，我只想知道是否至少有一条记录）。

关于我能做些什么不同以使其运行得更快的任何想法？

Answer 1

这是用适当的join语法重写的查询，更好的表别名和更少的括号::

SELECT COUNT(*) cnt
FROM PTYCHRG p JOIN
     AVAIL_ACTION_TYPE_CODES_TEMP atc
     ON TRIM(p.CASE_ID) = TRIM(atc.caseid) AND
        TRIM(atc.casecode) = TRIM(p.casecd) AND
        TRIM(atc.ACTIONCODE) IN (TRIM(p.ACTN_CD), TRIM(p.INDICTED_ACTN_CD), TRIM(p.AMENDED_ACTN_CD)) AND
        LOWER(TRIM(atc.DOMAIN)) = LOWER(TRIM(p.domain)) AND
 WHERE rownum = 1;

这些都没有解决任何问题。相反，它们可以更容易地解决问题。首先，您正在运行值的函数。这通常会阻止SQL Server使用索引，甚至可以对连接做出更明智的决策。如果空间确实存在问题，则有两种解决方案：功能索引或修复数据。我会修复数据：

update PTYCHRG
    set Case_Id = TRIM(Case_id),
        ActionCode = TRIM(ActionCode),
        ACTN_CD = TRIM(ACTN_CD),
        INDICTED_ACTN_CD = TRIM(INDICTED_ACTN_CD),
        AMENDED_ACTN_CD = TRIM(AMENDED_ACTN_CD),
        domain = lower(trim(domain));

update AVAIL_ACTION_TYPE_CODES_TEMP
    set caseid = trim(caseid),
        casecode = trim(casecode)
        ACTIONCODE = trim(ACTIONCODE),
        domain = lower(trim(domain));

然后查询变为：

SELECT  COUNT(*) cnt
FROM PTYCHRG p JOIN
     AVAIL_ACTION_TYPE_CODES_TEMP atc
     ON p.CASE_ID = atc.caseid AND
        atc.casecode = p.casecd AND
        atc.ACTIONCODE IN (p.ACTN_CD, p.INDICTED_ACTN_CD, p.AMENDED_ACTN_CD) AND
        atc.DOMAIN = p.domain AND
 WHERE rownum = 1;

然后我会推荐索引。你可以尝试：

create index idx_AVAIL_ACTION_TYPE_CODES_TEMP_4
    on AVAIL_ACTION_TYPE_CODES_TEMP(caseid, casecode, domain, actioncode)

Answer 2

赖安

您能看到，SQL是否与您的结果相同。

SELECT  COUNT(*) cnt
FROM    [PTYCHRG] A
JOIN    [AVAIL_ACTION_TYPE_CODES_TEMP] B
ON      TRIM(A.CASE_ID) = TRIM(caseid)
AND     ISNULL(TRIM(A.ACTN_CD),ISNULL(TRIM(A.INDICTED_ACTN_CD),TRIM(A.AMENDED_ACTN_CD))) = TRIM(B.ACTIONCODE)
WHERE   [rownum] = 1

如果可以避免，请从sql中删除TRIM()

试图优化sql查询

2 个答案: