SQL move data from rows to cols - sql

Question

Sorry for the bad title - I simply do not know what to call the thing I want to do.
Here it goes:
In MS SQL Server 2008
I have a temp table with 4000+ rows created with the WITH statement looking like this:
ID (varchar) DATE (int)
AB1135000097 | 20151221
AB1135000097 | 20160119
AB1135000097 | 20160219
AB1135001989 | 20120223
AB1135001989 | 20120323
AB1135001989 | 20120423
.
.
.
I want to pair the data in date-ranges based on DATE.
AB1135000097 | 20151221 | 20160119
AB1135000097 | 20160119 | 20160219
AB1135001989 | 20120223 | 20120323
AB1135001989 | 20120323 | 20120423
Does this action have a name ? (I will add tags to the post when I know what I'm asking for)

Answer 1

Assumed schema
I am assuming that your table is like:
CREATE TABLE "TABLE"
(
tag CHAR(1) NOT NULL,
value INTEGER NOT NULL,
PRIMARY KEY(tag, value)
);
I really shouldn't have to guess the schema though.
Possible answer
Superficially, you might be after:
SELECT t1.tag, t1.value, t2.value
FROM "TABLE" AS t1
JOIN "TABLE" AS t2
ON t1.tag = t2.tag AND t2.value = t1.value + 1
ORDER BY t1.tag, t1.value;
This joins the table with itself, combining rows where the tag column values (A, B, ...) are the same, and where the value column in one row is one more than the value column in the other.
On the other hand, if you add a row ('A', 5) to the table and expect it to appear in the output as part of a row ('A', 3, 5), then the query is much harder to write without using OLAP features.

Answer 2

if you are using Oracle database then you can refer following query to solve this question -
with t as
(
SELECT 'A' Col1, 1 Col2
FROM Dual
UNION ALL
SELECT 'A' Col1, 2 Col2
FROM Dual
UNION ALL
SELECT 'A' Col1, 3 Col2
FROM Dual
UNION ALL
SELECT 'B' Col1, 4 Col2
FROM Dual
UNION ALL
SELECT 'B' Col1, 5 Col2
FROM Dual
UNION ALL
SELECT 'B' Col1, 6 Col2 FROM Dual
)
SELECT *
FROM (SELECT Col1,
Col2,
Lead(Col1) Over(ORDER BY Col1, Col2) Col3,
Lead(Col2) Over(ORDER BY Col1, Col2) Col4
FROM t --(your table name)
ORDER BY Col1, Col2)
WHERE Col1 = Col3
as I don't have your table name and table structure I have created one temp table in Query itself.
you need to change From t to From with your table name . .. please change col1 and col2 column name also accordingly.

Answer 3

I found a solution to my problem. Inspired by Jonathan Leffler's solution. Thanks a lot!
It is based on adding row-numbers to the table ordered by ID and DATE, and then self-join with ROW+1 to get the next date as a second date column.
with
SCHEDULE as
( -- remove duplicates and NULL entries
select DISTINCT ID, DATE from TABLE1
where DATE IS NOT NULL
),
SCHEDULE_WITH_ROW as
(
select * from (
select DISTINCT ROW_NUMBER()
OVER (ORDER BY ID, DATE) AS
ROW, ID, DATE
from SCHEDULE) AS SCHED
)
select
S1.ID
, S1.DATE
, S2.DATE
from SCHEDULE_WITH_ROW S1
join SCHEDULE_WITH_ROW S2 on S2.ID = S1.ID and S1.ROW + 1 = S2.ROW