Question

我有一个包含4个字段的表（id，Year，Week，Totals）。

我需要一个查询，我想使用join，根据年份和周字段填充零值。

在我的例子中，我需要填写第3周和第4周/年的零值

Rec Id, Year, Week, Totals
1, '2012', '52', '23'
2, '2013', '1' , '9'
3, '2013', '2' , '4'

Missing record from DB -> null, '2013', '3' , '0'
Missing record from DB -> null, '2013', '4' , '0'

4, '2013', '5' , '5'
5, '2013', '6' , '6'
6, '2013', '7' , '5'

Answer 1

这是一个有趣的！好的，我们走了。首先，我会给你一个简单的版本，它依赖于几个假设：

您的表格中每年至少有一个条目
在任何特定年份，您的表中每周至少有一次。 IE：此查询返回从1到52的所有数字：

从您的__table中选择DISTINCT周

鉴于这些限制，此查询应该按您的要求执行：

INSERT INTO your_table (id, year, week, totals)
    SELECT null, y, w, 0 FROM (
        SELECT DISTINCT week w FROM your_table
    ) weeks
    CROSS JOIN 
    (
        SELECT DISTINCT year y FROM your_table
    ) years
    WHERE
        (y > (select min(year) from your_table) OR w > (select min(week) from your_table where `year`=y))
        AND
        (y < (select max(year) from your_table) OR w < (select max(week) from your_table where `year`=y))
        AND 
        NOT EXISTS (select year, week from your_table where `year`=y AND `week`=w)

如果条件2可能不满意 - 如果每年都缺少一些周，则可以替换此行

SELECT DISTINCT week w FROM your_table

与

SELECT
    (TWO_1.SeqValue + TWO_2.SeqValue + TWO_4.SeqValue + TWO_8.SeqValue + TWO_16.SeqValue + TWO_32.SeqValue) w
FROM
    (SELECT 0 SeqValue UNION ALL SELECT 1 SeqValue) TWO_1
    CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 2 SeqValue) TWO_2
    CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 4 SeqValue) TWO_4
    CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 8 SeqValue) TWO_8
    CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 16 SeqValue) TWO_16
    CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 32 SeqValue) TWO_32
HAVING w >= 1 AND w <= 52

给出更一般的案例：

INSERT INTO your_table (id, year, week, totals)
    SELECT null, y, w, 0 FROM (
        SELECT
            (TWO_1.SeqValue + TWO_2.SeqValue + TWO_4.SeqValue + TWO_8.SeqValue + TWO_16.SeqValue + TWO_32.SeqValue) w
        FROM
            (SELECT 0 SeqValue UNION ALL SELECT 1 SeqValue) TWO_1
            CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 2 SeqValue) TWO_2
            CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 4 SeqValue) TWO_4
            CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 8 SeqValue) TWO_8
            CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 16 SeqValue) TWO_16
            CROSS JOIN (SELECT 0 SeqValue UNION ALL SELECT 32 SeqValue) TWO_32
        HAVING w >= 1 AND w <= 52
    ) weeks
    CROSS JOIN 
    (
        SELECT DISTINCT year y FROM your_table
    ) years
    WHERE
        (y > (select min(year) from your_table) OR w > (select min(week) from your_table where `year`=y))
        AND
        (y < (select max(year) from your_table) OR w < (select max(week) from your_table where `year`=y))
        AND 
        NOT EXISTS (select year, week from your_table where `year`=y AND `week`=w)

（如果不满足条件1，你可以使用类似的技术来生成年份列表，但我猜你没有完整的年度漏洞。）

最后，如果你有一年和一周的唯一索引，这可以简化一点。如果您还没有这样的索引，可以像这样创建它：

ALTER TABLE `your_table` ADD CONSTRAINT date UNIQUE (
`year`,
`week`
)

如果你愿意，你可以在完成后删除它，如下所示：

ALTER TABLE `your_table` DROP INDEX date;

在这种情况下，可以删除where子句的最后一部分：

AND 
NOT EXISTS (select year, week from your_table where `year`=y AND `week`=w)

因为INSERT IGNORE将跳过已存在该唯一年/周组合的任何行。

对范围生成代码的答案赞不绝口：https://stackoverflow.com/a/8349837/160565

如何填补每周数据的空白？

1 个答案: