Left join producing wrong result, Sql Server

Left join producing wrong result

create table contacttype(ctype_id int,ctype varchar(20))
insert contacttype values
( 12	,'Ctype1'),
( 13	,'Ctype2'),
( 14	,'Ctype3')

create table contacts(cid int,ctype_id int,name varchar(20), phone varchar(15))
insert contacts values
(1001,	12	,'Tim',	1234567890),
(1001,	13	,'Joe',	9874563210),
(1001,	14	,'Jack',	6547893214),
(1002,	12	,'Jane',	6547896125),
(1002,	13	,'Smith',	null),
(1002,	14	,'Jill',	9878445623 )

select c.cid,
	   max(case when ct.ctype = 'Ctype1' then c.name end) as [ctype1_name],
	   c1.phone,
	   max(case when ct.ctype = 'Ctype2' then c.name end) as [ctype2_name],
	   c2.phone,
	   max(case when ct.ctype = 'Ctype3' then c.name end) as [ctype3_name],
	   c3.phone
from contacts c
join contacttype ct on c.ctype_id = ct.ctype_id
left join contacts c1 on c1.ctype_id = ct.ctype_id and ct.ctype = 'Ctype1'
left join contacts c2 on c2.ctype_id = ct.ctype_id and ct.ctype = 'Ctype2'
left join contacts c3 on c3.ctype_id = ct.ctype_id and ct.ctype = 'Ctype3'
group by c.cid,c1.phone,c2.phone,c3.phone


run \| edit \| history \| help	0

Please log in to post a comment.

Advertise here.