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I have a table which contains the following:

Table1

ID Range        Rate
1  A,B,C,D,E,F   1.2
2  A,B,C         3.1

and another table:

Table2

ID A B C D E F G H J K
1  1 2 1 3 4 2 4 5 8 1     
2  1 2 1 3 4 2 4 5 8 1

Basically this tells us which columns we can apply the rate to, e.g we can apply the rate 1.2 to values that are stored in columns A,B,C,D,E,F of table2 and rate of 3.2 should be applied to columns A,B and C only.

I am joining the two table on the ID column

Select * From Table1 
Inner Join Table2 ON Table1.ID = Table2.ID

But what I am trying to achieve is after joining the 2 tables to select the columns from Table2 based on the contents of the Range column of Table1.

Based on the above example, from the Table1 the first column's range field has: A,B,C,D,E,F so from Table2, I am trying to select only columns A,B,C,D,E,F and apply the rate (1.2) to all of them and leave the rest of the columns untouched, so the solution will look like this:

ID A       B     C      D      E      F      G  H   J  K
1  1*1.2  2*1.2  1*1.2  3*1.2  4*1.2  2*1.2  4  5   8  1
2  1*3.1  2*3.1  1*3.1  3      4      2      4  5   8  1

Hope this makes sense.

Thanks

4

2 回答 2

2

不是很好（非常脆弱），但是：

select  case when 'A' in t1.Range then t2.a * t1.rate else t2.a else end a,
        case when 'B' in t1.Range then t2.b * t1.rate else t2.b else end b,
        case when 'C' in t1.Range then t2.c * t1.rate else t2.c else end c,
        case when 'D' in t1.Range then t2.d * t1.rate else t2.d else end d,
        ...
from    Table1 t1 left join Table2 t2 on t1.id = t2.id
于 2013-05-24T12:01:52.480 回答
2

您正在以逗号分隔的列表中查找子字符串。执行此操作的 SQL 标准方法是使用like：

select t2.id,
       t2.a * (case when ','||Range||',' like '%,A,%' then t1.rate else 1 else end) as a,
       t2.b * (case when ','||Range||',' like '%,B,%' then t1.rate else 1 else end) as b,
       t2.c * (case when ','||Range||',' like '%,C,%' then t1.rate else 1 else end) as c,
       t2.d * (case when ','||Range||',' like '%,D,%' then t1.rate else 1 else end) as d,
       t2.e * (case when ','||Range||',' like '%,E,%' then t1.rate else 1 else end) as e,
       t2.f * (case when ','||Range||',' like '%,F,%' then t1.rate else 1 else end) as f,
       t2.g * (case when ','||Range||',' like '%,G,%' then t1.rate else 1 else end) as g,
       t2.h * (case when ','||Range||',' like '%,H,%' then t1.rate else 1 else end) as h,
       t2.j * (case when ','||Range||',' like '%,J,%' then t1.rate else 1 else end) as j,
       t2.k * (case when ','||Range||',' like '%,K,%' then t1.rate else 1 else end) as k
from Table1 t1 left join
     Table2 t2
     on t1.id = t2.id;

具体来说，这是对范围进行分隔，因此每个值前后都有一个逗号（包括第一个和最后一个）。然后它正在寻找每个值的模式。

我应该提到，这种类型的查询表明数据结构不佳。您的 Table1 每个值应该有单独的行。

于 2013-05-24T13:15:03.523 回答