如何让 sql 在同一行而不是多行中打印（db 是 db2）

Question

我有 2 个表需要从中选择数据。

表 1：

ID	name
1	John
2	Mark
3	Anna

表2：

Person_ID	type	year
1	born	1920
1	graduated	1950
1	died	2000
2	born	1940
2	graduated	1960
2	died	2011

我想编写一个查询，将它们全部放入同一行：

id	name	born	grad	died
1	John	1920	1950	2000

我试过了：

SELECT
    t1.id AS id, t1.name AS name, 
    CASE WHEN t2.type = 'born' THEN t2.year END AS born,
    CASE WHEN t2.type = 'graduated' THEN t2.year END AS grad,
    CASE WHEN t2.type = 'died' THEN t2.year END AS died
FROM
    table1 t1 
INNER JOIN 
    table2 t2 ON t1.id = t2.Person_ID
WHERE
    t1.id = 1 
GROUP BY
    t1.id, t1.name, t2.type, t2.year

这是我现在得到的结果：

id	name	born	grad	died
1	John	1920	null	null
1	John	null	1950	null
1	John	null	null	2000

Answer 1

使用旋转逻辑：

SELECT
    t1.ID,
    t1.name,
    MAX(CASE WHEN t2.type = 'born'      THEN t2.year END) AS born,
    MAX(CASE WHEN t2.type = 'graduated' THEN t2.year END) AS grad,
    MAX(CASE WHEN t2.type = 'died'      THEN t2.year END) AS died
FROM table1 t1
INNER JOIN table2 t2
    ON t2.Person_ID = t1.ID
GROUP BY
    t1.ID,
    t1.name
ORDER BY
    t1.ID;