数据库多行转一个行的问题 - V2EX
V2EX = way to explore
V2EX 是一个关于分享和探索的地方
Sign Up Now
For Existing Member  Sign In
请不要在回答技术问题时复制粘贴 AI 生成的内容
7911364440

数据库多行转一个行的问题

  •  
  •   7911364440 Apr 24, 2023 1541 views
    This topic created in 1112 days ago, the information mentioned may be changed or developed.

    数据库用的 Oracle 。

    多行数据根据 code 字段合并为一行,再根据 type 字段判断:

    • 当 type=1 时,该行的 field1, field2, field3 = value1, value2, value3
    • 当 type=2 时,该行的 field1, field2, field3 = value4, value5, value6
    • 当 type=3 时,该行的 field1, field2, field3 = value7, value8, value9
    3 replies    2023-04-24 11:41:05 +08:00
    Jf35jxN3fwBXyeLh
        1
    Jf35jxN3fwBXyeLh  
       Apr 24, 2023
    以前有个网站好像叫 帮你百度一下,以后可能会有 帮你 ChatGPT 一下 这种网站,以下是来自 chatgpt 的回答:
    您可以使用 Oracle 的 PIVOT 和 UNPIVOT 函数来实现根据 code 字段合并行并按照 type 字段转换列的操作。具体实现过程将包括以下步骤:

    1.使用 PIVOT 函数将具有相同 code 值的多行数据合并为单个行。
    2.使用 UNPIVOT 函数将 type 字段转换为列并将对应的值填入相应的字段中。
    3.使用 SELECT 语句来检索结果。

    下面是一个示例 SQL 查询:
    SELECT * FROM
    (
    SELECT code, type, field1, field2, field3
    FROM your_table
    )
    PIVOT
    (
    MAX(field1) AS field1, MAX(field2) AS field2, MAX(field3) AS field3
    FOR type IN (1, 2, 3)
    )
    UNPIVOT
    (
    value
    FOR (field, type) IN ((field1, 1), (field2, 1), (field3, 1), (field1, 2), (field2, 2), (field3, 2), (field1, 3), (field2, 3), (field3, 3))
    );
    这将返回一个结果集,其中每个行包含相同的 code 值,以及列名( field )和相应的值( value )。
    ccraohng
        2
    ccraohng  
       Apr 24, 2023
    CASE 就行
    SELECT CASE WHEN xxx TEHN 1 END
    /tr>
    chosen1cwp
        3
    chosen1cwp  
       Apr 24, 2023
    select GROUP_CONCAT(concat("'",name,"'")) from table group by field
    About     Help     Advertise     Blog     API     FAQ     Solana     2953 Online   Highest 6679       Select Language
    创意工作者们的社区
    World is powered by solitude
    VERSION: 3.9.8.5 38ms UTC 09:59 PVG 17:59 LAX 02:59 JFK 05:59
    Do have faith in what you're doing.
    ubao msn snddm index pchome yahoo rakuten mypaper meadowduck bidyahoo youbao zxmzxm asda bnvcg cvbfg dfscv mmhjk xxddc yybgb zznbn ccubao uaitu acv GXCV ET GDG YH FG BCVB FJFH CBRE CBC GDG ET54 WRWR RWER WREW WRWER RWER SDG EW SF DSFSF fbbs ubao fhd dfg ewr dg df ewwr ewwr et ruyut utut dfg fgd gdfgt etg dfgt dfgd ert4 gd fgg wr 235 wer3 we vsdf sdf gdf ert xcv sdf rwer hfd dfg cvb rwf afb dfh jgh bmn lgh rty gfds cxv xcv xcs vdas fdf fgd cv sdf tert sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf shasha9178 shasha9178 shasha9178 shasha9178 shasha9178 liflif2 liflif2 liflif2 liflif2 liflif2 liblib3 liblib3 liblib3 liblib3 liblib3 zhazha444 zhazha444 zhazha444 zhazha444 zhazha444 dende5 dende denden denden2 denden21 fenfen9 fenf619 fen619 fenfe9 fe619 sdf sdf sdf sdf sdf zhazh90 zhazh0 zhaa50 zha90 zh590 zho zhoz zhozh zhozho zhozho2 lislis lls95 lili95 lils5 liss9 sdf0ty987 sdft876 sdft9876 sdf09876 sd0t9876 sdf0ty98 sdf0976 sdf0ty986 sdf0ty96 sdf0t76 sdf0876 df0ty98 sf0t876 sd0ty76 sdy76 sdf76 sdf0t76 sdf0ty9 sdf0ty98 sdf0ty987 sdf0ty98 sdf6676 sdf876 sd876 sd876 sdf6 sdf6 sdf9876 sdf0t sdf06 sdf0ty9776 sdf0ty9776 sdf0ty76 sdf8876 sdf0t sd6 sdf06 s688876 sd688 sdf86