如何测试源中的行值是否作为目标中的列

Question

我有一个如下所示的源表，

身份证	专栏	价值
1	苹果	10
1	苹果	8
1	香蕉	9
1	香蕉	12

我有一个如下所示的目标表，

身份证	苹果	香蕉
1	10	9
1	8	12

如何使用雪花测试/验证这一点

Answer 1

with src_data(id, col, val) as (
    select * from values
        (1  ,'apple',   10),
        (1  ,'apple',   8),
        (1  ,'banana',  9),
        (1  ,'banana',  12)
), target_data(id, apple, banana) as (
    select * from values
        (1, 10, 9),
        (1, 8,  12),
        (2, 10, 9),
        (1, 10, 13),
        (1, 7, 12)
)
select t.*
    ,a.val as a_val
    ,b.val as b_val
from target_data as t
left join src_data as a
    on t.id = a.id 
        and a.col = 'apple'
        and t.apple = a.val 
left join src_data as b
    on t.id = b.id 
        and b.col = 'banana'
        and t.banana = b.val                

展示了如何使用允许遗漏的 LEFT JOIN 连接数据：

所以现在我们只需将它们更改为 INNER JOINS，并且仅输出

t.*

值：

select t.*
from target_data as t
join src_data as a
    on t.id = a.id 
        and a.col = 'apple'
        and t.apple = a.val 
join src_data as b
    on t.id = b.id 
        and b.col = 'banana'
        and t.banana = b.val 

我们得到过滤后的结果：

身份证	苹果	香蕉
1	10	9
1	8	12