合并gridview行并消除重复

I have 2 tables:

我有两个表:

Table 1

id   question   customerId
1     bla1         1
2     bla2         2    

Table 2

id    customerId    Key         Value
1      1           firstname    John
2      1           lastname     Doe
3      2           firstname    Billy
4      2           lastname     Jones
Table 1

id   quest