将多行连接到一个字段中

Question

我有一个表像三列像图像(源),并希望编写一个查询,给出像图像一样的表(结果)

Answer 1

SELECT DISTINCT customer,
    stuff((
            SELECT ',' + cast(policy as varchar(10))
            FROM table1 b
            WHERE a.customerid = b.customerid
            FOR XML path('')
            ), 1, 1, '') [policies]
FROM table1 a