[英]Select all columns with only two distinct columns
In my SQL Server database, I have a table with many duplicate values and I need to fetch results with distinct columns EID
and YEAR
and select rows containing fewer NULL values or order the table and get a final DISTINCT column EID and YEAR rows. In my SQL Server database, I have a table with many duplicate values and I need to fetch results with distinct columns EID
and YEAR
and select rows containing fewer NULL values or order the table and get a final DISTINCT column EID and YEAR rows.
For example: below the table with EID = E138442 and YEAR = 2019 occurs 21 times were in this duplicate the row containing fewer null values should be fetched例如:在 EID = E138442 和 YEAR = 2019 的表下方出现 21 次,在此重复中,应获取包含较少 null 值的行
+---------+------+------+------+------+------+------+------+------+------+------+------+------+------+
| EID | YEAR | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC |
+---------+------+------+------+------+------+------+------+------+------+------+------+------+------+
| E050339 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 1 |
| E050339 | 2020 | NULL | 6 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL |
| E050339 | 2020 | 13 | 6 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL |
| E138348 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 1 | NULL |
| E138348 | 2019 | NULL | 1 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL |
| e138372 | 2019 | 1 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL |
| E138440 | 2019 | NULL | NULL | 2 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL |
| E138442 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 5 |
| E138442 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 9 | 5 |
| E138442 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 9 | 5 |
| E138442 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 4 | 9 | 5 |
| E138442 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 4 | 9 | 5 |
| E138442 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 4 | 9 | 5 |
| E138442 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 4 | 9 | 5 |
| E138442 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 4 | 9 | 5 |
| E138442 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 4 | 4 | 9 | 5 |
| E138442 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 7 | 4 | 4 | 9 | 5 |
| E138442 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 7 | 4 | 4 | 9 | 5 |
| E138442 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | 7 | 7 | 4 | 4 | 9 | 5 |
| E138442 | 2019 | NULL | NULL | NULL | NULL | NULL | NULL | 7 | 7 | 4 | 4 | 9 | 5 |
| E138442 | 2019 | NULL | NULL | NULL | NULL | NULL | 2 | 7 | 7 | 4 | 4 | 9 | 5 |
| E138442 | 2019 | NULL | NULL | NULL | NULL | 7 | 2 | 7 | 7 | 4 | 4 | 9 | 5 |
| E138442 | 2019 | NULL | NULL | NULL | 7 | 7 | 2 | 7 | 7 | 4 | 4 | 9 | 5 |
| E138442 | 2019 | NULL | NULL | 1 | 7 | 7 | 2 | 7 | 7 | 4 | 4 | 9 | 5 |
| E138442 | 2019 | NULL | 1 | NULL | 7 | 7 | 2 | 7 | 7 | 4 | 4 | 9 | 5 |
| E138442 | 2020 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 1 |
| E138442 | 2020 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 1 |
| E138442 | 2020 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 1 |
| E138442 | 2020 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 1 |
+---------+------+------+------+------+------+------+------+------+------+------+------+------+------+
I need a SQL query to fetch values as shown here:我需要一个 SQL 查询来获取值,如下所示:
+---------+------+------+------+------+------+------+------+------+------+------+------+------+------+
| EID | YEAR | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC |
+---------+------+------+------+------+------+------+------+------+------+------+------+------+------+
| E050339 | 2020 | 13 | 6 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL |
| E138348 | 2019 | NULL | 1 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL |
| e138372 | 2019 | 1 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL |
| E138440 | 2019 | NULL | NULL | 2 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL |
| E138442 | 2019 | NULL | 1 | NULL | 7 | 7 | 2 | 7 | 7 | 4 | 4 | 9 | 5 |
| E138442 | 2020 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 1 |
+---------+------+------+------+------+------+------+------+------+------+------+------+------+------+
The result table should have a final row with distinct columns EID and YEAR.结果表的最后一行应该有不同的列 EID 和 YEAR。
SELECT *
FROM TABLE_NAME C1
WHERE EXISTS (SELECT 1
FROM TABLE_NAME C2
WHERE C1.EID = C2.EID AND C1.YEAR = C2.YEAR
HAVING COUNT(*) = 1)
ORDER BY
c1.EID, c1.YEAR, c1.JAN, c1.FEB, c1.MAR, c1.APR,
c1.MAY, c1.JUN, c1.JUL, c1.AUG, c1.SEP, c1.OCT, c1.NOV, c1.DEC ASC;
I tried the above code but found irrelevant results我尝试了上面的代码,但发现了不相关的结果
since you have no other way to distinguish members of a group and based on "select rows containing fewer NULL values " here is one way how you can do it by using ctes, its not clean but probably the only way:因为您没有其他方法来区分组的成员,并且基于“选择包含较少 NULL 值的行”,这是您可以通过使用 ctes 来做到这一点的一种方法,它不干净但可能是唯一的方法:
with cte as (
SELECT *,
ISNULL(c1.JAN, 1) + ISNULL(c1.FEB,1) + ... + ISNULL(c1.DEC,1) AS NullCount
FROM
tablename
)
, cte2 as (
select EID , YEAR , min(NullCount) min_nullcount
from cte
group by EID , YEAR
)
select t.*
from
cte t
join cte2 tt
on t.EID = tt.EID
and t.YEAR = tt.YEAR
and t.NULLCount = tt.min_nullcount
If you have duplicate minimum null per group you can use query below:如果每个组有重复的最小 null,您可以使用以下查询:
select * from (
SELECT *,
ROW_NUMBER OVER (partition by EID , YEAR order by ISNULL(c1.JAN, 1) + ... + ISNULL(c1.DEC,1) AS rnk
FROM
tablename
) xx
WHERE rnk = 1
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