Find distinct from a comma separated values in ANSI SQL. I am trying this on DB2 database.
Scenario
Id Val
1 A,B,C
2 A,D,A,C,B
3 B,A,C,C,D
Expected output
Id Val
1 A,B,C
2 A,D,C,B
3 B,A,C,D
DB2 offers a way to tokens strings using XML. Using this, you can split the string into tokens and then use listagg(distinct):
select v.id, listagg(distinct tokens.token, ',')
from (values (1, 'A,B,C'), (2, 'A,D,A,C,B'), (3, 'B,A,C,C,D')) v(id, val),
xmltable('for $id in tokenize($s, ",") return <i>{string($id)}</i>' passing v.val as "s"
columns seq for ordinality, token varchar(20) path '.'
) tokens
group by v.id;
Here is a db<>fiddle.
Note: I strongly recommend that you fix the data model. Storing multiple values in a string is bad way to store data in any database.
Depending on your platform and version of Db2, you may have the functions SPLIT() and LISTAGG() available.
with dist as (
select
distinct id, element
from tbl, table(split(val,','))
)
select
id
, listagg(element) within group (order by column_values)
as disinct_list
from dist
group by id
;
EDIT
corrected name of the column returned by SPLIT(), IBM provided version is ELEMENT we happened to have an older User Defined version that used COLUMN_VALUE.
Related
I have a column which has inconsistent data. The column named ID and it can have values such as
0897546321
ABC,0876455321
ABC,XYZ,0873647773
ABC,
99756
test only
The SQL query should fetch only Ids which are of 10 digit in length, should begin with a 08 , should be not null and should not contain all characters. And for those values, which have both digits and characters such as ABC,XYZ,0873647773, it should only fetch the 0873647773 . In these kind of values, nothing is fixed, in place of ABC, XYZ , it can be anything and can be of any length.
The column Id is of varchar type.
My try: I tried the following query
select id
from table
where id is not null
and id not like '%[^0-9]%'
and id like '[08]%[0-9]'
and len(id)=10
I am still not sure how should I deal with values like ABC,XYZ,0873647773
P.S - I have no control over the database. I can't change its values.
SQL Server generally has poor support regular expressions, but in this case a judicious use of PATINDEX is viable:
SELECT SUBSTRING(id, PATINDEX('%,08[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9],%', ',' + id + ','), 10) AS number
FROM yourTable
WHERE ',' + id + ',' LIKE '%,08[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9],%';
Demo
If you normalise your data, and split the delimited data into parts, you can achieve this some what more easily:
SELECT SS.value
FROM dbo.YourTable YT
CROSS APPLY STRING_SPLIT(YT.YourColumn,',') SS
WHERE LEN(SS.value) = 10
AND SS.value NOT LIKE '%[^0-9]%';
If you're on an older version of SQL Server, you'll have to use an alternative String Splitter method (such as a XML splitter or user defined inline table-value function); there are plenty of examples on these already on Stack Overflow.
db<>fiddle
I have a table with a column code containing multiple pieces of data like this:
001/2017/TT/000001
001/2017/TT/000002
001/2017/TN/000003
001/2017/TN/000001
001/2017/TN/000002
001/2016/TT/000001
001/2016/TT/000002
001/2016/TT/000001
002/2016/TT/000002
There are 4 items in 001/2016/TT/000001: 001, 2016, TT and 000001.
How can I extract the max for every group formed by the first 3 items? The result I want is this:
001/2017/TT/000003
001/2017/TN/000002
001/2016/TT/000002
002/2016/TT/000002
Edit
The subfield separator is /, and the length of subfields can vary.
I use PostgreSQL 9.3.
Obviously, you should normalize the table and split the combined string into 4 columns with proper data type. The function split_part() is the tool of choice if the separator '/' is constant in your string and the length of can vary.
CREATE TABLE tbl_better AS
SELECT split_part(code, '/', 1)::int AS col_1 -- better names?
, split_part(code, '/', 2)::int AS col_2
, split_part(code, '/', 3) AS col_3 -- text?
, split_part(code, '/', 4)::int AS col_4
FROM tbl_bad
ORDER BY 1,2,3,4 -- optionally cluster data.
Then the task is trivial:
SELECT col_1, col_2, col_3, max(col_4) AS max_nr
FROM tbl_better
GROUP BY 1, 2, 3;
Related:
Split comma separated column data into additional columns
Of course, you can do it on the fly, too. For varying subfield length you could use substring() with a regular expression like this:
SELECT max(substring(code, '([^/]*)$')) AS max_nr
FROM tbl_bad
GROUP BY substring(code, '^(.*)/');
Related (with basic explanation for regexp pattern):
Filter strings with regex before casting to numeric
Or to get only the complete string as result:
SELECT DISTINCT ON (substring(code, '^(.*)/'))
code
FROM tbl_bad
ORDER BY substring(code, '^(.*)/'), code DESC;
About DISTINCT ON:
Select first row in each GROUP BY group?
Be aware that data items cast to a suitable type may behave differently from their string representation. The max of 900001 and 1000001 is 900001 for text and 1000001 for integer ...
Use the LEFT and RIGHT functions.
SELECT MAX(RIGHT(code,6)) AS MAX_CODE
FROM yourtable
GROUP BY LEFT(code,12)
check this out, possible helpfull
select
distinct on (tab[4],tab[2]) tab[4],tab[3],tab[2],tab[1]
from
(
select
string_to_array(exe.x,'/') as tab,
exe.x
from
(
select
unnest
(
array
['001/2017/TT/000001',
'001/2017/TT/000002',
'001/2017/TN/000003',
'001/2017/TN/000001',
'001/2017/TN/000002',
'001/2016/TT/000001',
'001/2016/TT/000002',
'001/2016/TT/000001',
'002/2016/TT/000002']
) as x
) exe
) exe2
order by tab[4] desc,tab[2] desc,tab[3] desc;
i'm using presto. I have an ID field which is numeric. I want a column that adds up the digits within the id. So if ID=1234, I want a column that outputs 10 i.e 1+2+3+4.
I could use substring to extract each digit and sum it but is there a function I can use or simpler way?
You can combine regexp_extract_all from #akuhn's answer with lambda support recently added to Presto. That way you don't need to unnest. The code would be really self explanatory if not the need for cast to and from varchar:
presto> select
reduce(
regexp_extract_all(cast(x as varchar), '\d'), -- split into digits array
0, -- initial reduction element
(s, x) -> s + cast(x as integer), -- reduction function
s -> s -- finalization
) sum_of_digits
from (values 1234) t(x);
sum_of_digits
---------------
10
(1 row)
If I'm reading your question correctly you want to avoid having to hardcode a substring grab for each numeral in the ID, like substring (ID,1,1) + substring (ID,2,1) + ...substring (ID,n,1). Which is inelegant and only works if all your ID values are the same length anyway.
What you can do instead is use a recursive CTE. Doing it this way works for ID fields with variable value lengths too.
Disclaimer: This does still technically use substring, but it does not do the clumsy hardcode grab
WITH recur (ID, place, ID_sum)
AS
(
SELECT ID, 1 , CAST(substring(CAST(ID as varchar),1,1) as int)
FROM SO_rbase
UNION ALL
SELECT ID, place + 1, ID_sum + substring(CAST(ID as varchar),place+1,1)
FROM recur
WHERE len(ID) >= place + 1
)
SELECT ID, max(ID_SUM) as ID_sum
FROM recur
GROUP BY ID
First use REGEXP_EXTRACT_ALL to split the string. Then use CROSS JOIN UNNEST GROUP BY to group the extracted digits by their number and sum over them.
Here,
WITH my_table AS (SELECT * FROM (VALUES ('12345'), ('42'), ('789')) AS a (num))
SELECT
num,
SUM(CAST(digit AS BIGINT))
FROM
my_table
CROSS JOIN
UNNEST(REGEXP_EXTRACT_ALL(num,'\d')) AS b (digit)
GROUP BY
num
;
I have the following data:
name id url
John 1 someurl.com
Matt 2 cool.com
Sam 3 stackoverflow.com
How can I write an SQL statement in Postgres to select this data into a multi-dimensional array, i.e.:
{{John, 1, someurl.com}, {Matt, 2, cool.com}, {Sam, 3, stackoverflow.com}}
I've seen this kind of array usage before in Postgres but have no idea how to select data from a table into this array format.
Assuming here that all the columns are of type text.
You cannot use array_agg() to produce multi-dimensional arrays, at least not up to PostgreSQL 9.4.
(But the upcoming Postgres 9.5 ships a new variant of array_agg() that can!)
What you get out of #Matt Ball's query is an array of records (the_table[]).
An array can only hold elements of the same base type. You obviously have number and string types. Convert all columns (that aren't already) to text to make it work.
You can create an aggregate function for this like I demonstrated to you here before.
CREATE AGGREGATE array_agg_mult (anyarray) (
SFUNC = array_cat
,STYPE = anyarray
,INITCOND = '{}'
);
Call:
SELECT array_agg_mult(ARRAY[ARRAY[name, id::text, url]]) AS tbl_mult_arr
FROM tbl;
Note the additional ARRAY[] layer to make it a multidimensional array (2-dimenstional, to be precise).
Instant demo:
WITH tbl(id, txt) AS (
VALUES
(1::int, 'foo'::text)
,(2, 'bar')
,(3, '}b",') -- txt has meta-characters
)
, x AS (
SELECT array_agg_mult(ARRAY[ARRAY[id::text,txt]]) AS t
FROM tbl
)
SELECT *, t[1][3] AS arr_element_1_1, t[3][4] AS arr_element_3_2
FROM x;
You need to use an aggregate function; array_agg should do what you need.
SELECT array_agg(s) FROM (SELECT name, id, url FROM the_table ORDER BY id) AS s;
I have one table A that has a column C and a lookup table (lookup) that provides a description given an ID.
Here the setup:
table A with column C values:
1,2,3
2,3,4
table lookup:
1, 'This'
2, 'is'
3, 'tricky'
4, 'SQL'
Provide a SQL (SQL Server 2005) statement that returns the following strings:
Input: 1,2,3 Output: 'This','Is','tricky'
Input: 2,3,4 Output: 'Is','tricky','SQL'
basically turning the string of IDs (from an input table A) into a string of descriptions
The Samples that come with SQL Server 2005 include a CLR function called Split(). It's the best way of splitting comma-separated lists like this by far.
Suppose you have a table called inputs, with a column called input.
I forget what the particular outputs of dbo.Split() are... so work with me here. Let's call the fields id and val, where id tells us which entry it is in the list.
WITH
separated AS (
SELECT i.input, s.id, s.val
FROM
dbo.inputs AS i
CROSS APPLY
dbo.Split(i.input) AS s
)
, converted AS (
SELECT s.input, s.id, m.string
FROM
separated AS s
JOIN
dbo.mapping AS m
ON m.number = CAST(s.val AS varchar(5))
)
SELECT c.input, (SELECT string + ' ' FROM converted AS c2 WHERE c2.input = c.input ORDER BY id FOR XML PATH('')) AS converted_string
FROM converted AS c
GROUP BY c.input;