(A.FBILLNO + '_' +N.FSEQ)

This appears to be a concatenated string made up of two parts:

1. A.FBILLNO: This likely refers to a field or column name in a database table, representing a bill number.
2. '_' : This is a underscore character, used as a separator between the first and second parts of the concatenated string.
3. N.FSEQ: This likely refers to another field or column name in a database table, representing a sequence number.

Together, these parts create a unique identifier for a specific bill and its sequence number. For example, if A.FBILLNO is "12345" and N.FSEQ is "1", the concatenated string would be "12345_1".

相关问题

优化这段代码 SELECT distinct top 200 FBarcode, --明码 \n" + FSecretBarcode, --暗码\n" + FMATERIALNUMBER, --产品编码\n" + FMATERIALNAME, --产品名称\n" + FBILLNO, --生产任务号\n" + FPackageNo, --箱码\n" + //2022-09-04新增 FSPECIFICATION, --规格型号\n" + FDATE, --日期\n" + B.F_LPS_ZLDJ1 AS F_LP_ZJDJ, --质量等级\n" + B.F_LPS_WLTX1 AS F_LP_NDDJ, --粘度等级\n" + FQTY --0未传输 1已传输\n" + FROM DB2BARCODE A LEFT JOIN LPMDBS.LOPAL2020.DBO.T_BD_MATERIAL B ON A.FMATERIALNUMBER=B.FNUMBER WHERE ISNULL(A.FSecretBarcode,'')<>'' AND A.FDATE >'2023-06-01 00:00:00' AND FQTY IS NULL AND FSecretBarcode NOT IN ( SELECT-- distinct top 1000 FSecretBarcode --暗码\n" + FROM DB2BARCODE A LEFT JOIN LPMDBS.LOPAL2020.DBO.T_BD_MATERIAL B ON A.FMATERIALNUMBER=B.FNUMBER WHERE ISNULL(A.FSecretBarcode,'')<>'')

为了优化这段代码，可以考虑以下几点：

1. 使用 `INNER JOIN` 替代 `LEFT JOIN`：根据查询条件，如果不需要左连接的功能，可以改用内连接（`INNER JOIN`），这样可以提高查询性能。

2. 使用索引：为 `DB2BARCODE` 表的 `FSecretBarcode` 和 `F` 列创建索引，以加快查询速度。

3. 使用上限限制：对于子查询中的 `TOP 1000`，可以根据具体需求进行适当调整，以减少子查询的执行时间。

下面是优化后的代码示例：

SELECT TOP 200
    A.FBarcode,         --明码 \n" +
    A.FSecretBarcode,   --暗码\n" +
    A.FMATERIALNUMBER,  --产品编码\n" +
    A.FMATERIALNAME,    --产品名称\n" +
    A.FBILLNO,          --生产任务号\n" +                                   
    A.FPackageNo,       --箱码\n" +  //2022-09-04新增
    A.FSPECIFICATION,   --规格型号\n" +
    A.FDATE,             --日期\n" +
    B.F_LPS_ZLDJ1 AS F_LP_ZJDJ,     --质量等级\n" +
    B.F_LPS_WLTX1 AS F_LP_NDDJ,     --粘度等级\n" +
    A.FQTY               --0未传输   1已传输\n" +
FROM 
    DB2BARCODE A
INNER JOIN 
    LPMDBS.LOPAL2020.DBO.T_BD_MATERIAL B ON A.FMATERIALNUMBER = B.FNUMBER
WHERE 
    A.FSecretBarcode <> '' 
    AND A.FDATE > '2023-06-01 00:00:00' 
    AND A.FQTY IS NULL
    AND A.FSecretBarcode NOT IN (
        SELECT TOP 1000 FSecretBarcode   --暗码\n" +
        FROM DB2BARCODE
        WHERE FSecretBarcode <> ''
    )

请注意，优化代码时要根据实际情况进行测试和调整，并确保索引和表名的正确性。

优化以下sql查询语句："select t_ICItemCore.FItemID,t_ICItemCore.fshortnumber,t_ICItemCore.fname,ICBOMChild.FScrap, PPBom.FBillNo,ICItemScrapEntry.FAuxQty,PPBomEntry.FAuxStockQty from dbo.t_ICItemCore INNER JOIN dbo.ICBOMChild ON dbo.t_ICItemCore.FItemID = dbo.ICBOMChild.FItemID INNER JOIN dbo.PPBom ON dbo.ICBOMChild.FItemID = dbo.PPBom.FItemID INNER JOIN dbo.ICItemScrapEntry ON dbo.PPBom.FItemID = dbo.ICItemScrapEntry.FItemID INNER JOIN dbo.PPBomEntry ON dbo.PPBom.FItemID = dbo.PPBomEntry.FItemID"

可以尝试以下优化措施：

1. 添加索引：对于t_ICItemCore表的FItemID列、ICBOMChild表的FItemID列、PPBom表的FItemID列、ICItemScrapEntry表的FItemID列和PPBomEntry表的FItemID列，分别添加索引可以提高查询速度。

2. 减少表连接次数：将PPBomEntry表和ICItemScrapEntry表的连接改为子查询，可以减少表连接次数。

优化后的SQL查询语句：

SELECT t_ICItemCore.FItemID, t_ICItemCore.fshortnumber, t_ICItemCore.fname, ICBOMChild.FScrap, PPBom.FBillNo, ICItemScrapEntry.FAuxQty, 
       (SELECT PPBomEntry.FAuxStockQty FROM dbo.PPBomEntry WHERE dbo.PPBomEntry.FItemID = dbo.PPBom.FItemID) AS FAuxStockQty
FROM dbo.t_ICItemCore 
INNER JOIN dbo.ICBOMChild ON dbo.t_ICItemCore.FItemID = dbo.ICBOMChild.FItemID 
INNER JOIN dbo.PPBom ON dbo.ICBOMChild.FItemID = dbo.PPBom.FItemID 
INNER JOIN dbo.ICItemScrapEntry ON dbo.PPBom.FItemID = dbo.ICItemScrapEntry.FItemID