How do I get records before and after given one?
I have the following table structure:
Id, Message
1, John Doe
2, Jane Smith
3, Error
4, Jane Smith
开发者_开发问答Is there a way to get the error record and the surrounding records? i.e. find all Errors and the record before and after them.
;WITH numberedlogtable AS
(
SELECT Id,Message,
ROW_NUMBER() OVER (ORDER BY ID) AS RN
FROM logtable
)
SELECT Id,Message
FROM numberedlogtable
WHERE RN IN (SELECT RN+i
FROM numberedlogtable
CROSS JOIN (SELECT -1 AS i UNION ALL SELECT 0 UNION ALL SELECT 1) n
WHERE Message='Error')
WITH err AS
(
SELECT TOP 1 *
FROM log
WHERE message = 'Error'
ORDER BY
id
),
p AS
(
SELECT TOP 1 l.*
FROM log
WHERE id <
(
SELECT id
FROM err
)
ORDER BY
id DESC
)
SELECT TOP 3 *
FROM log
WHERE id >
(
SELECT id
FROM p
)
ORDER BY
id
Adapt this routine to pick out your target.
DECLARE @TargetId int
SET @TargetId = 3
select *
from LogTable
where Id in (-- "before"
select max(Id)
from LogTable
where Id < @TargetId
-- target
union all select @TargetId
-- "after"
union all select min(Id)
from LogTable
where Id > @TargetId)
select id,messag from
(Select (Row_Number() over (order by ID)) as RNO, * from #Temp) as A,
(select SubRNO-1 as A,
SubRNO as B,
SubRNO+1 as C
from (Select (Row_Number() over (order by ID)) as SubRNO, * from #Temp) as C
where messag = 'Error') as B
where A.RNO = B.A or A.RNO = B.B or A.RNO = B.C
;WITH Logs AS
(
SELECT ROW_NUMBER() OVER (ORDER BY id), id, message as rownum FROM LogTable lt
)
SELECT curr.id, prev.id, next.id
FROM Logs curr
LEFT OUTER JOIN Logs prev ON curr.rownum+1=prev.rownum
RIGHT OUTER JOIN Logs next ON curr.rownum-1=next.rownum
WHERE curr.message = 'Error'
select id, message from tbl where id in (
select id from tbl where message = "error"
union
select id-1 from tbl where message = "error"
union
select id+1 from tbl where message = "error"
)
Get fixed number of rows before & after target
Using UNION for a simple, high performance query (I found selected answer WITH query above to be extremely slow)
Here is a high performance alternative to the WITH top selected answer, when you know an ID or specific identifier for a given record, and you want to select a fixed number of records BEFORE and AFTER that record. Requires a number field for ID, or something like date that can be sorted ascending / descending.
Example: You want to select the 10 records before and after a specific error was recorded, you know the error ID, and can sort by date or ID.
The following query gets (inclusive) the 1 result above, the identified record itself, and the 1 record below. After the UNION, the results are sorted again in descending order.
SELECT q.*
FROM(
SELECT TOP 2
id, content
FROM
the_table
WHERE
id >= [ID]
ORDER BY id ASC
UNION
SELECT TOP 1
id, content
FROM
the_table
WHERE
id < [ID]
ORDER BY id DESC
) q
ORDER BY q.id DESC
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