How to create separate rows for each unique value in source data - sql

Question

I have following table:
Cus_ID Work_Phone Home_Phone Mobile_Phone
1 x Blank x
2 x x Blank
3 x x x
.
.
. and so on (1000s of rows)
Work_Phone, Home_Phone, Mobile_Phone - varchar
x = some value present
I need to select from Source data to move it Target system like below, I need to create separate row for unique values for each Cus_ID. How do i do it?
Cus_ID Type ContactNo
1 Work x
1 Mobile x
2 Work x
2 Home x
3 Work x
3 Home x
3 Mobile x
.. and so on
Type, ContactNo - varchar
x = Should be the corresponding value from Source table

Answer 1

above result we can achieve using UNPIVOT or Cross Apply also by basing on your assumed data
declare #t table (PK varchar(1),col1 varchar(1),col2 varchar(1),col3 varchar(1))
insert into #t(PK,col1,col2,col3)values
('X','a','','c'),
('y','a','b',''),
('z','a','b','c')
Cross Apply :
select PK,value
from #t
cross apply
(
values
('I1', col1),
('I2', col2),
('I3', col3)
) c(col, value)
where value is not null AND value <> ''
order by PK, col
UNPIVOT
select PK,value
from #t
unpivot
(
value
for col in (col1, col2, col3)
) un
WHERE value <> ''
order by PK, col;

Answer 2

Assuming col1, col2 and col3 are of the same type, then:
SELECT pk, col2 AS target_value FROM your_table WHERE col2 IS NOT NULL
UNION
SELECT pk, col3 AS target_value FROM your_table WHERE col3 IS NOT NULL
UNION
SELECT pk, col4 AS target_value FROM your_table WHERE col4 IS NOT NULL
ORDER BY pk
Edit edit: here's the version with ISNULL tests, column headings and the rest, in response to your revised question:
SELECT Cus_ID, 'Work' AS Type, Work_Phone AS ContactNo FROM your_table
WHERE ISNULL(Work_Phone, '') <> ''
UNION
SELECT Cus_ID, 'Home' AS Type, Home_Phone AS ContactNo FROM your_table
WHERE ISNULL(Home_Phone, '') <> ''
UNION
SELECT Cus_ID, 'Mobile' AS Type, Mobile_Phone AS ContactNo FROM your_table
WHERE ISNULL(Mobile_Phone, '') <> ''
ORDER BY 1
If there's a chance the "blank" column may contain whitespace characters, then refine it yet further to:
... ISNULL(LTRIM(Work_Phone), '') <> ''
etc.