sql - 如何在 SQL 的行中合并非空值

Question

我有以下情况：

COL_1   COL_2   COL_3   COL_4   COL_5   COL_6   COL_7
5678      ?        ?       ?       ?       ?    ?
?        6789      ?       ?       ?       ?    ?
?         ?      1223      ?       ?       ?    ?
?         ?        ?      1223     ?       ?    ?
?         ?        ?       ?       1223    ?    ?
?         ?        ?       ?       ?       1223 ?
?         ?        ?       ?       ?       ?    12823

我想要这个：

COL_1   COL_2   COL_3   COL_4   COL_5   COL_6   COL_7
5678    6789    1223    1223    1223    1223    12823

我尝试使用 COLAESCE () 函数，但这似乎没有将列作为参数。

Answer 1

MAX()如果每一行都有一个值，您可以只在下面的所有列上使用：

CREATE TABLE #data
(
    col1 INT,
    col2 INT,
    col3 INT
);

INSERT INTO #data
(
    col1,
    col2,
    col3
)
VALUES
(1, NULL, NULL),
(NULL, 2, NULL),
(NULL, NULL, 3);

SELECT MAX(d.col1) AS col1,
       MAX(d.col2) AS col2,
       MAX(d.col3) AS col3
FROM #data AS d;

DROP TABLE #data;

Answer 2

SELECT   SUM( ISNULL(COL1,0)) AS COL_1
        ,SUM(ISNULL(COL2,0)) AS COL_2
        ,SUM(ISNULL(COL3,0)) AS COL_3
        ,SUM(ISNULL(COL4,0)) AS COL_4
        ,SUM(ISNULL(COL5,0)) AS COL_5
        ,SUM(ISNULL(COL6,0)) AS COL_6
        ,SUM(ISNULL(COL7,0)) AS COL_7
FROM YOUR_TABLE

Answer 3

使用 COLAESCE 会将所有结果输出到一列中。使用诸如 group by 或其中列不等于“？”之类的参数

Answer 4

SELECT
    (SELECT TOP(1) col1 FROM Table1 WHERE col1 IS NOT NULL ORDER BY SortCol) AS col1,
    (SELECT TOP(1) col2 FROM Table1 WHERE col2 IS NOT NULL ORDER BY SortCol) AS col2,
    (SELECT TOP(1) col3 FROM Table1 WHERE col3 IS NOT NULL ORDER BY SortCol) AS col3,
    (SELECT TOP(1) col4 FROM Table1 WHERE col4 IS NOT NULL ORDER BY SortCol) AS col4,
    (SELECT TOP(1) col5 FROM Table1 WHERE col5 IS NOT NULL ORDER BY SortCol) AS col5,
    (SELECT TOP(1) col6 FROM Table1 WHERE col6 IS NOT NULL ORDER BY SortCol) AS col6,
    (SELECT TOP(1) col7 FROM Table1 WHERE col7 IS NOT NULL ORDER BY SortCol) AS col7