大家好，想请教一下如何将三张表合并成一张表
三张表分别为
PP1
Product_name num1
A 2
B 3
C 6
D 7
PP2
Product_name num2
E 3
A 2
B 1
PP3
Product_name num3
F 2
G 5
C 8
SQL里如何写语句成为下面的表
PP
Product_name num1 num2 num3
A 2 2 0
B 3 1 0
C 6 0 8
D 7 0 0
E 0 3 0
F 0 0 2
G 0 0 5
------解决方案--------------------
- SQL code
create table PP1(Product_name varchar(3),num1 int)create table PP2(Product_name varchar(3),num2 int)create table PP3(Product_name varchar(3),num3 int)insert into PP1select 'A', 2 union allselect 'B', 3 union allselect 'C', 6 union allselect 'D', 7insert into PP2select 'E', 3 union allselect 'A', 2 union allselect 'B', 1insert into PP3select 'F', 2 union allselect 'G', 5 union allselect 'C', 8select coalesce(a.Product_name,b.Product_name,c.Product_name) 'Product_name', isnull(a.num1,0) 'num1', isnull(b.num2,0) 'num2', isnull(c.num3,0) 'num3'into PP from PP1 afull join PP2 b on a.Product_name=b.Product_namefull join PP3 c on isnull(a.Product_name,b.Product_name)=c.Product_nameselect * from PPProduct_name num1 num2 num3------------ ----------- ----------- -----------A 2 2 0B 3 1 0C 6 0 8D 7 0 0E 0 3 0F 0 0 2G 0 0 5(7 row(s) affected)