使用联接联接两个表

Question

我有两个下表。我想保留t1以外的所有内容，以及t2以外的所有其他内容，除了Date，Id。两个表的指标值（工资，奖金）均不得更改。由于t1中有多个日期和ID，因此输出中出现重复。我的代码如下。请协助。

从t1中选择t1。*，t2。* except（Date，Id） 左加入t2 在t1.Date = t2。日期 和t1.Id = t2.Id

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Answer 1

虽然输出表的逻辑可能缺乏解释，但我可以回答您的主要问题。您可以使用LEFT JOIN并简单地手动SELECT从每个表中获取所需的所有列，并以所需的顺序将其写入。

下面是我创建的一些示例数据的语法。

with t1 as (
SELECT DATE(2020,01,22) as Date, 1 as id, "abc" as Name, "NYC" as City, "USA" as Country, 5000 as Salary UNION ALL
SELECT DATE(2020,01,23) as Date, 2 as id, "abc" as Name, "SF" as City, "USA" as Country, 8000 as Salary UNION ALL
SELECT DATE(2020,01,22) as Date, 2 as id, "abc" as Name, "SF" as City, "USA" as Country, 8000 as Salary
), 
t2 as (
SELECT DATE(2020,01,22) as Date, 1 as id, "Man" as Position, "1st" as Rank, 1000 as Bonus UNION ALL
SELECT DATE(2020,01,22) as Date, 2 as id, "Man" as Position, "1st" as Rank, 1000 as Bonus
)
SELECT t1.Date, t1.id, t1.Name, t1.City, t2.Position, t2.Rank, t1.Country, t1.Salary, 
         t2.Bonus  
FROM t1 LEFT JOIN t2 on t1.Date=t2.Date and t1.id=t2.id

输出，

请注意，我已经按照希望它们在输出中的顺序选择了列。此外，Date和id来自select语句中指定的表1。另一个重要的一点是，在t1.Date=t2.Date and t1.id=t2.id未被检查为true的情况下，分配给t2的列的值为null。

我想指出的是，我只是作为示例手动设置了Rank列的值。最后，with()中的所有内容都是示例数据。