Question

我从3个表中获取记录：

(
    SELECT
        f.id AS id,
        'Faktura VAT' as type,
        DATE_FORMAT(f.date_issue, '%d.%m.%Y') AS date_issue
    FROM Invoice_vat f
)
UNION ALL
(
    SELECT
        f.id AS id,
        'Faktura korygująca' as type,
        DATE_FORMAT(f.date_issue, '%d.%m.%Y') AS date_issue
    FROM Invoice_fks f
)
UNION ALL
(
    SELECT
        f.id AS id,
        'Faktura proforma' as type,
        DATE_FORMAT(f.date_issue, '%d.%m.%Y') AS date_issue
    FROM Invoice_pro f
)
ORDER BY date_issue DESC

我尝试使用字段“date_issue”对此进行排序，但这不起作用......有什么想法吗？

Answer 1

按“date_issue”排序。问题在于它是一种糟糕的格式，即月中的第一天。因此，列表可能从1月1日开始，但2月1日在1月2日之前开始。我将通过使用规范格式YYYY-MM-DD（日期的ISO标准格式）来解决此问题。

您也可以通过在输出中包含原始列来轻松解决此问题：

(
    SELECT
        f.id AS id,
        'Faktura VAT' as type,
        DATE_FORMAT(f.date_issue, '%d.%m.%Y') AS date_issue,
        f.date_issue as orig_date_issue
    FROM Invoice_vat f
)
UNION ALL
(
    SELECT
        f.id AS id,
        'Faktura korygująca' as type,
        DATE_FORMAT(f.date_issue, '%d.%m.%Y') AS date_issue,
        f.date_issue as orig_date_issue
    FROM Invoice_fks f
)
UNION ALL
(
    SELECT
        f.id AS id,
        'Faktura proforma' as type,
        DATE_FORMAT(f.date_issue, '%d.%m.%Y') AS date_issue,
        f.date_issue as orig_date_issue
    FROM Invoice_pro f
)
ORDER BY orig_date_issue DESC;

如果您实际上不想选择该字段，则可以使用子查询。

Answer 2

您按照date_issue的修改版进行排序，因此它将排序为字符串，而不是日期。

尝试对最后的日期进行格式化，而不是针对每个Union进行格式化：

Select  ID, 
        Type, 
        DATE_FORMAT(date_issue, '%d.%m.%Y') As Date_Issue
From
(
    (
        SELECT
            f.id AS id,
            'Faktura VAT' as type,
            f.date_issue
        FROM Invoice_vat f
    )
    UNION ALL
    (
        SELECT
            f.id AS id,
            'Faktura korygująca' as type,
            f.date_issue
        FROM Invoice_fks f
    )
    UNION ALL
    (
        SELECT
            f.id AS id,
            'Faktura proforma' as type,
            f.date_issue
        FROM Invoice_pro f
    )
) A
ORDER BY A.date_issue DESC

UNION ALL - ORDER BY，排序

2 个答案: