转换从SQL Server的功能到MS Access

Question

我有一些代码设计在表中插入值，写在SQL Server：

创建表/建模式：

CREATE TABLE Inter 
    ([id] int, [MarkDate] date, [MaturityDate] date, [ZeroRate] int) 
; 

INSERT INTO Inter 
    ([id], [MarkDate], [MaturityDate], [ZeroRate]) 

VALUES 
    (1, '2015-07-02', '2015-07-02', 1), 
    (2, '2015-07-02', '2015-07-03', 5), 
    (3, '2015-07-02', '2015-07-06', 15) 
; 


CREATE TABLE allDates 
    ([id] int, [MaturityDate] date) 
; 

INSERT INTO allDates 
    ([id], [MaturityDate]) 

VALUES 
    (1, '2015-07-01'), 
    (2, '2015-07-02'), 
    (3, '2015-07-03'), 
    (4, '2015-07-04'), 
    (5, '2015-07-05'), 
    (6, '2015-07-06'), 
    (7, '2015-07-07'), 
    (8, '2015-07-08'), 
    (9, '2015-07-09') 
; 

CREATE TABLE rangesInter 
    ([id] int, [MarkDate] date, [begindate] date, [enddate] date, startRate float, rateChange float); 


INSERT INTO rangesInter 
    SELECT 
     I1.id, 
     I1.[MarkDate], 
     I1.[MaturityDate] begindate, 
     I2.[MaturityDate] enddate, 
     I1.[ZeroRate] startRate, 
     (I2.ZeroRate - I1.ZeroRate) * 1.0/DATEDIFF (day , I1.[MaturityDate], I2.[MaturityDate]) rateChange   
    FROM Inter I1 
    inner join Inter I2 
    on I1.id = I2.id - 1; 

插入值：

SELECT 
    IIF(i.MarkDate IS NULL, r.MarkDate, i.MarkDate) as MarkDate, 
    a.MaturityDate, 
    IIF(i.ZeroRate IS NULL, 
      r.startRate + DATEDIFF (day , r.begindate, a.MaturityDate) * rateChange, 
      i.ZeroRate) as ZeroRate, 
    i.*, r.* 
FROM 
    allDates a 
LEFT JOIN 
    Inter I ON a.MaturityDate = I.MaturityDate 
CROSS JOIN 
    (SELECT 
     MIN(MaturityDate) minDate, MAX(MaturityDate) maxDate 
    FROM Inter) AS t 
LEFT JOIN 
    (SELECT 
     I1.id, I1.[MarkDate], 
     I1.[MaturityDate] begindate, I2.[MaturityDate] enddate, 
     I1.[ZeroRate] startRate, 
     (I2.ZeroRate - I1.ZeroRate) * 1.0/DATEDIFF (day , I1.[MaturityDate], I2.[MaturityDate]) rateChange   
    FROM 
     Inter I1 
    INNER JOIN 
     Inter I2 ON I1.id = I2.id - 1) r ON a.MaturityDate > r.[begindate] 
              AND a.MaturityDate < r.[enddate] 
WHERE 
    a.MaturityDate >= t.minDate 
    AND a.MaturityDate <= t.maxDate; 

我怎么会去这个代码转换到MS Access VBA？

我不知道如何开始转换代码的“插入值”部分与Access VBA工作。

Answer 1

我很想知道为什么要转换这是在访问VBA。

我将建立查询SQL作为VBA字符串，然后创建一个从SQL字符串QueryDef对象。

在构建SQL字符串时，您会发现this回答可帮助您。

一些更实际点显示在下面的SQL：

在你的代码中删除笛卡儿连接，明确如下。

所有列的别名和表的别名需要一个 “AS”

相反IIF的，你可以使用

nz(MyFieldWithNulls, AnotherfieldToBeUsedWhenItisNull) 

更换DATEDIFF如图

SELECT Nz(i.MarkDate, r.MarkDate) as MarkDate 
    , a.MaturityDate 
    , Nz(i.ZeroRate 
     , r.startRate + Cint(a.MaturityDate - r.begindate) * rateChange 
     ) as ZeroRate 
    , i.* 
    , r.* 
FROM ( (SELECT allDates.* 
      FROM allDates 
       INNER JOIN (SELECT MIN(MaturityDate) AS minDate 
            , MAX(MaturityDate) AS maxDate 
           FROM Inter 
          ) AS Inter 
         ON (allDates.MaturityDate >= Inter.minDate 
           AND 
           allDates.MaturityDate <= Inter.maxDate 
          ) 
     ) AS a 
     LEFT JOIN Inter AS I 
       ON a.MaturityDate = I.MaturityDate 
    ) 
    LEFT JOIN (SELECT , I1.id 
         , I1.[MarkDate] 
         , I1.[MaturityDate] AS begindate 
         , I2.[MaturityDate] AS enddate, 
         , I1.[ZeroRate]  AS startRate, 
         , (I2.ZeroRate - I1.ZeroRate) * 1.0 
         /DATEDIFF (day , I1.[MaturityDate], I2.[MaturityDate]) 
          AS rateChange   
        FROM Inter I1 
         INNER JOIN Inter I2 
           ON I1.id = (I2.id - 1) 
       ) AS r 
      ON (a.MaturityDate > r.[begindate] 
       AND 
       a.MaturityDate < r.[enddate] 
       )  
    ; 

Answer 2

有几点让你开始：

IIf存在于访问了，所以没有必要改变这种状况。

的CROSS JOIN关键字访问不存在;在表名/子查询之间使用逗号（,）来返回笛卡尔积。您可能还需要您ON声明指的是笛卡尔乘积移动到WHERE条款。

当你在访问一个ON条款多个项目，他们需要用括号包围。例如：

... ON (f1.ID = f2.ID AND f1.Name = f3.Name) ... 

另外，当您在Access SQL语句中连接多个表时，每个表都必须用圆括号包围。例如： -

SELECT ... 
FROM 
    ((Table1 t1 
     INNER JOIN Table2 t2 ON t1.ID = t2.ID) 
     INNER JOIN Table3 t3 ON t1.ID = t3.ID) 
     INNER JOIN Table4 t4 ON t1.ID = t4.ID 

混合一起在一个单一的查询类型时，您可能会收到错误（如笛卡尔，左内）。如果是这样，我建议将查询分解成几个Access查询，每个Access查询都有相似的连接类型，然后在另一个查询中将这些部分连接在一起。分解这个问题也可以帮助您简化从SQL Server的转换。

访问也有类似于SQL Server的一个DateDiff功能。但是，第一个参数是表示间隔的字符串（例如，day =“d”，month =“m”等）。所以，你可以像这样替换你DATEDIFF功能：

DateDiff("d", I1.[MaturityDate], I2.[MaturityDate])