良いパフォーマンスでサブクエリを削除するにはどうすればいいですか

Question

ここではサブクエリを良好なパフォーマンスで削除できますか？このサブクエリを追加すると、正しい出力が得られますが、利用可能なレコード数のため検索が遅くなります。しかし、これを取り除いた後は、複数の折り目で増加します。誰でもこのサブクエリを省略したり、以下のクエリを改善するのに役立つことができます。多分

SELECT insurance_folder_cnt, MAX(lapsed_date) lapseddate 
FROM insurance_file ifl 
WHERE insurance_file_status_id=1 AND insurance_file_type_id in (2, 5, 6, 8, 9) AND (ISNULL(Base_Insurance_File_Cnt,0) = 0 OR ISNULL(Base_Insurance_File_Cnt, 0) = insurance_file_cnt) AND ISNULL(out_of_sequence_replaced, 0) = 0 
AND policy_version = (SELECT MAX(policy_version) FROM Insurance_File ifld WHERE ifl.insurance_folder_cnt=ifld.insurance_folder_cnt) GROUP BY insurance_folder_cnt having policy_version = max(policy_version) 

Answer 1

Please use this for better performance: 

SELECT insurance_folder_cnt , 
     MAX(lapsed_date) lapseddate 
FROM insurance_file ifl 
     CROSS APPLY (SELECT MAX(policy_version) AS maxVersion 
         FROM  Insurance_File ifld 
        ) TmpMaxVersion 
WHERE insurance_file_status_id = 1 
     AND insurance_file_type_id IN (2, 5, 6, 8, 9) 
     AND (ISNULL(Base_Insurance_File_Cnt, 0) = 0 
       OR ISNULL(Base_Insurance_File_Cnt, 0) = insurance_file_cnt 
      ) 
     AND ISNULL(out_of_sequence_replaced, 0) = 0 
     AND policy_version = TmpMaxVersion.maxVersion 
GROUP BY insurance_folder_cnt 
HAVING policy_version = MAX(policy_version) 

Answer 2

：あなたはまた、ISNULL関数を置き換えることができます

SELECT insurance_folder_cnt, MAX(lapsed_date) lapseddate 
FROM insurance_file ifl 
join (select insurance_folder_cnt inffld, max(policy_version) pol_ver from insurace_file group by insurance_folder_cnt) ifld 
on (ifld.inffld = ifl.insurance_folder_cnt and pol_ver = ifl.policy_version) 
WHERE insurance_file_status_id=1 AND insurance_file_type_id in (2, 5, 6, 8, 9) 
AND (ISNULL(Base_Insurance_File_Cnt,0) = 0 OR ISNULL(Base_Insurance_File_Cnt, 0) = insurance_file_cnt) 
AND ISNULL(out_of_sequence_replaced, 0) = 0 
GROUP BY insurance_folder_cnt 

：

(Base_Insurance_File_Cnt is null OR Base_Insurance_File_Cnt = insurance_file_cnt)