table 中有多个记录时增加列

Question

我对这类问题很陌生。我试过寻找但找不到任何东西。我还尝试使用每次都递增的 Case 表达式，但这不起作用。

tblHipChop

hop    acp      ID
20     20       amdb_ma_se_1234
350    30       amdb_ma_se_1234

必须return以下内容：

hop_a    hcp_b    acp_a     acp_b     ID
20       350      20        30        amdb_ma_se_1234

Answer 1

DECLARE @tblHipChop TABLE (hop INT, [acp] INT, ID VARCHAR(50))

INSERT INTO @tblHipChop
VALUES (20, 20, 'amdb_ma_se_1234'), (350, 30, 'amdb_ma_se_1234')

SELECT
    hop_a = MAX(CASE WHEN t.RowNum = 1 THEN hop END),
    hcp_b = MAX(CASE WHEN t.RowNum = 2 THEN hop END),
    acp_a = MAX(CASE WHEN t.RowNum = 1 THEN [acp] END),
    acp_b = MAX(CASE WHEN t.RowNum = 2 THEN [acp] END),
    ID
FROM (
    SELECT *, RowNum = ROW_NUMBER() OVER (PARTITION BY ID ORDER BY 1/0)
    FROM @tblHipChop
) t
GROUP BY t.ID

输出 -

hop_a       hcp_b       acp_a       acp_b       ID
----------- ----------- ----------- ----------- -----------------
20          350         20          30          amdb_ma_se_1234

查看 - ROW_NUMBER

table 中有多个记录时增加列

Increment columns when more than one record in table

sql

sql-server

sql-server-2014