How can I split a string in characters and add a new line after each character in PostgreSQL
For example
num desc
1 Hello
2 Bye
num desc
1 H
e
l
l
o
2 B
y
e
select num, regexp_split_to_table(descr,'')
from the_table
order by num;
SQLFiddle: http://sqlfiddle.com/#!15/13c00/4
The order of the characters is however not guaranteed and achieving that is a bit complicated.
Building on Erwin's answer regarding this problem:
select case
when row_number() over (partition by id order by rn) = 1 then id
else null
end as id_display,
ch_arr[rn]
from (
select *,
generate_subscripts(ch_arr, 1) AS rn
from (
select id,
regexp_split_to_array(descr,'') as ch_arr
from data
) t1
) t2
order by id, rn;
Edit:
If you just want a single string for each id, where the characters are separated by a newline, you can use this:
select id,
array_to_string(regexp_split_to_array(descr,''), chr(10))
from data
order by id
Related
I can't replace every 2 characters of a string with a '.'
select STUFF('abcdefghi', 3, 1, '.') c3,STUFF('abcdefghi', 5, 1,
'.') c5,STUFF('abcdefghi', 7, 1, '.') c7,STUFF('abcdefghi', 9, 1, '.')
c9
if I use STUFF I should subsequently overlap the strings c3, c5, c7 and c9. but I can't find a method
can you help me?
initial string:
abcdefghi
the result I would like is
ab.de.gh.
the string can be up to 50 characters
Create a numbers / tally / digits table, if you don't have one already, then you can use this to target each character position:
with digits as ( /* This would be a real table, here it's just to test */
select n from (values(1),(2),(3),(4),(5),(6),(7),(8),(9),(10))x(n)
), t as (
select 'abcdefghi' as s
)
select String_Agg( case when d.n%3 = 0 then '.' else Substring(t.s, d.n, 1) end, '')
from t
cross apply digits d
where d.n <Len(t.s)
Using for xml with existing table
with digits as (
select n from (values(1),(2),(3),(4),(5),(6),(7),(8),(9),(10))x(n)
),
r as (
select t.id, case when d.n%3=0 then '.' else Substring(t.s, d.n, 1) end ch
from t
cross apply digits d
where d.n <Len(t.s)
)
select result=(select '' + ch
from r r2
where r2.id=r.id
for xml path('')
)
from r
group by r.id
You can try it like this:
Easiest might be a quirky update ike here:
DECLARE #string VARCHAR(100)='abcdefghijklmnopqrstuvwxyz';
SELECT #string = STUFF(#string,3*A.pos,1,'.')
FROM (SELECT TOP(LEN(#string)/3) ROW_NUMBER() OVER(ORDER BY (SELECT NULL))
FROM master..spt_values) A(pos);
SELECT #string;
Better/Cleaner/Prettier was a recursive CTE:
We use a declared table to have some tabular sample data
DECLARE #tbl TABLE(ID INT IDENTITY, SomeString VARCHAR(200));
INSERT INTO #tbl VALUES('')
,('a')
,('ab')
,('abc')
,('abcd')
,('abcde')
,('abcdefghijklmnopqrstuvwxyz');
--the query
WITH recCTE AS
(
SELECT ID
,SomeString
,(LEN(SomeString)+1)/3 AS CountDots
,1 AS OccuranceOfDot
,SUBSTRING(SomeString,4,LEN(SomeString)) AS RestString
,CAST(LEFT(SomeString,2) AS VARCHAR(MAX)) AS Growing
FROM #tbl
UNION ALL
SELECT t.ID
,r.SomeString
,r.CountDots
,r.OccuranceOfDot+2
,SUBSTRING(RestString,4,LEN(RestString))
,CONCAT(Growing,'.',LEFT(r.RestString,2))
FROM #tbl t
INNER JOIN recCTE r ON t.ID=r.ID
WHERE r.OccuranceOfDot/2<r.CountDots-1
)
SELECT TOP 1 WITH TIES ID,Growing
FROM recCTE
ORDER BY ROW_NUMBER() OVER(PARTITION BY ID ORDER BY OccuranceOfDot DESC);
--the result
1
2 a
3 ab
4 ab
5 ab
6 ab.de
7 ab.de.gh.jk.mn.pq.st.vw.yz
The idea in short
We use a recursive CTE to walk along the string
we add the needed portion together with a dot
We stop, when the remaining length is to short to continue
a little magic is the ORDER BY ROW_NUMBER() OVER() together with TOP 1 WITH TIES. This will allow all first rows (frist per ID) to appear.
If I input a string as given below, I should be able to convert as mentioned below.
Ex 1: String - 5AB89C should be converted as 0000000005AB0000000089C
Ex 2: String GH1HJ should be converted as GH0000000001HJ
Ex 3: String N99K7H45 should be B0000000099K0000000007H0000000045
Each number should be complimented with 10 leading zeros including the number. In Ex:1, number 5 is complemented with 9 leading zeros making 10 digits, same way 89 is complimented with 8 leading zeros making total of 10 digits. Alphabets and any special characters should be untouched.
Once you get a copy of PatternSplitCM This is easy as pie.
Here's how we do it with one value:
DECLARE #string VARCHAR(8000) = '5AB89C'
SELECT CASE f.[matched] WHEN 1 THEN '00000000'+'' ELSE '' END + f.item
FROM dbo.patternsplitCM(#String,'[0-9]') AS f
ORDER BY f.ItemNumber
FOR XML PATH('');
Returns: 000000005AB0000000089C
Now against a table:
-- sample data
DECLARE #table TABLE (StringId INT IDENTITY, String VARCHAR(8000));
INSERT #table(String)
VALUES('5AB89C'),('GH1HJ'),('N99K7H45');
SELECT t.StringId, oldstring = t.String, newstring = f.padded
FROM #table AS t
CROSS APPLY
(
SELECT CASE f.[matched] WHEN 1 THEN '00000000'+'' ELSE '' END + f.item
FROM dbo.patternsplitCM(t.String,'[0-9]') AS f
ORDER BY f.ItemNumber
FOR XML PATH('')
) AS f(padded);
Returns:
StringId oldstring newstring
----------- ----------------- --------------------------------------
1 5AB89C 000000005AB0000000089C
2 GH1HJ GH000000001HJ
3 N99K7H45 N0000000099K000000007H0000000045
... and that's it. The code to create PatternSplitCM is below.
PatternSplitCM Code:
CREATE FUNCTION dbo.PatternSplitCM
(
#List VARCHAR(8000) = NULL
,#Pattern VARCHAR(50)
) RETURNS TABLE WITH SCHEMABINDING
AS
RETURN
WITH numbers AS (
SELECT TOP(ISNULL(DATALENGTH(#List), 0))
n = ROW_NUMBER() OVER(ORDER BY (SELECT NULL))
FROM
(VALUES (0),(0),(0),(0),(0),(0),(0),(0),(0),(0)) d (n),
(VALUES (0),(0),(0),(0),(0),(0),(0),(0),(0),(0)) e (n),
(VALUES (0),(0),(0),(0),(0),(0),(0),(0),(0),(0)) f (n),
(VALUES (0),(0),(0),(0),(0),(0),(0),(0),(0),(0)) g (n))
SELECT
ItemNumber = ROW_NUMBER() OVER(ORDER BY MIN(n)),
Item = SUBSTRING(#List,MIN(n),1+MAX(n)-MIN(n)),
Matched
FROM (
SELECT n, y.Matched, Grouper = n - ROW_NUMBER() OVER(ORDER BY y.Matched,n)
FROM numbers
CROSS APPLY (
SELECT Matched = CASE WHEN SUBSTRING(#List,n,1) LIKE #Pattern THEN 1 ELSE 0 END
) y
) d
GROUP BY Matched, Grouper
I have a column in a postgres database which logs search querystrings for a page on our website.
The column contains data like
"a=2&b=4"
"a=2,3"
"b=4&a=3"
"a=4&a=3"
I'd like to work out the frequency of each value for a certain parameter (a).
value | freq
------|------
3 | 3
2 | 2
4 | 1
Anyway to do this in a single SQL statement?
Something like this:
with all_values as (
select string_to_array(split_part(parameter, '=', 2), ',') as query_params
from the_table d,
unnest(string_to_array(d.querystring, '&')) as x(parameter)
where x.parameter like 'a%'
)
select t.value, count(*)
from all_values av, unnest(av.query_params) as t(value)
group by t.value
order by t.value;
Online example: http://rextester.com/OXM67442
try something like this :
select data_value,count(*) from (
select data_name,unnest(string_to_array(data_values,',')) data_value from (
select split_part(data_array,'=',1) data_name ,split_part(data_array,'=',2) data_values from (
select unnest(string_to_array(mydata,'&')) data_array from mytable
) a
) b
) c where data_name='a' group by 1 order by 1
Assuming tha table that keeps the counts is called paramcount:
WITH vals(v) AS
(SELECT regexp_replace(p, '^.*=', '')
FROM regexp_split_to_table(
'b=4&a=3,2',
'&|,'
) p(p)
)
INSERT INTO paramcount (value, freq)
SELECT v, 1 FROM vals
ON CONFLICT (value)
DO UPDATE SET freq = paramcount.freq + 1
WHERE paramcount.value = EXCLUDED.value;
get csv integer after 'a='
split that to numbers
stat values
select v, count(*) from (
SELECT c,unnest(string_to_array(unnest(regexp_matches(c,'a=([0-9,]+)','g')),',')) as v FROM qrs
) x group by v;
Parametrize:
WITH argname(aname) as (values ('a'::TEXT))
select v, count(*) from (SELECT c,unnest(string_to_array(unnest(regexp_matches(c,aname||'=([0-9,]+)','g')),',')) as v FROM qrs,argname) x group by v;
I am using SQL server 2008R2 and have a table called AirNewformat .This table is mostly searched by ID column which has many duplicates. I wanted to update same table by adding a column called processed where first value of ID is updated as 'N' in processed column and rest of the duplicates updated as 'D' in the processed column. Currently i have all the records updated either as N or D but i want see an update like below example. Any help is greatly appreciated.
ID Processed
--- ---------
12 N
12 D
12 D
13 N
13 D
13 D
Please try this code if you might ( SQL Fiddle for this: http://sqlfiddle.com/#!3/03991/6 ):
Update first record in every ID group as N:
UPDATE
A
SET
A.Processed = 'N'
FROM
(
SELECT ID, Processed, ROW_NUMBER() OVER(ORDER BY ID) AS row_num FROM AirNewformat
) AS A
INNER JOIN
(
SELECT
C.ID,
MIN(C.row_num) AS min_row_num
FROM
(
SELECT ID, ROW_NUMBER() OVER(ORDER BY ID) AS row_num FROM AirNewformat
) AS C
GROUP BY C.ID
) AS B ON A.ID = B.ID AND A.row_num = B.min_row_num;
Update all the rest of records as D:
UPDATE
AirNewformat
SET
AirNewformat.Processed = 'D'
WHERE
ISNULL(AirNewformat.Processed, '') = '';
You can try this:
;with cte as
(
select ROW_NUMBER() over (PARTITION by ID order by ID) N, processed from airNewformat
)
update cte
set processed = case when N = 1 then 'N'
when N >1 then 'D' end;
I have one main table called Event_log which contains all of the records that I need for this query. Within this table there is one column that I'm calling "Grp". To simplify things, assume that there are only two possible values for this Grp: A and B. So now we have one table, Event_log, with one column "Grp" and one more column called "Actual Date". Lastly I want to add one more Flag column to this table, which works as follows.
First, I order all of the records in descending order by date as demonstrated below. Then, I want to flag each Group "A" row with a 1 or a 0. For all "A" rows, if the previous record (earlier in date) = "B" row then I want to flag 1. Otherwise flag a 0. So this initial table looks like this before setting this flag:
Actual Date Grp Flag
1-29-13 A
12-27-12 B
12-26-12 B
12-23-12 A
12-22-12 A
But after these calculations are done, it should look like this:
Actual Date Grp Flag
1-29-13 A 1
12-27-12 B NULL
12-26-12 B NULL
12-23-12 A 0
12-22-12 A 0
How can I do this? This is simpler to describe than it is to query!
You can use something like:
select el.ActualDate
, el.Grp
, Flag = case
when el.grp = 'B' then null
when prev.grp = 'B' then 1
else 0
end
from Event_log el
outer apply
(
select top 1 prev.grp
from Event_log prev
where el.ActualDate > prev.ActualDate
order by prev.ActualDate desc
) prev
order by el.ActualDate desc
SQL Fiddle with demo.
Try this
;with cte as
(
SELECT CAST('01-29-13' As DateTime) ActualDate,'A' Grp
UNION ALL SELECT '12-27-12','B'
UNION ALL SELECT '12-26-12','B'
UNION ALL SELECT '12-23-12','A'
UNION ALL SELECT '12-22-12','A'
)
, CTE2 as
(
SELECT *, ROW_NUMBER() OVER (order by actualdate desc) rn
FROM cte
)
SELECT a.*,
case
when A.Grp = 'A' THEN
CASE WHEN b.Grp = 'B' THEN 1 ELSE 0 END
ELSE NULL
END Flag
from cte2 a
LEFT OUTER JOIN CTE2 b on a.rn + 1 = b.rn