Calculate the number of values ​in each field separately in SQL - sql

I have this table like this:
Column A
Column B
Column C
B
1
w
B
2
e
A
1
p
I want to get result like this:
Column
CountByValue
B
2
A
1
1
2
2
1
w
1
e
1
p
1
Is there any way to get the above result with SQL? Thanks.


It can be done like following also using CROSS APPLY
SELECT V.[Column],COUNT(*) CountByValue
FROM MyTable T
CROSS APPLY (
SELECT [Column]
FROM (
VALUES (T.ColumnA),(T.ColumnB),(T.ColumnC)) v([Column])
) v
GROUP BY V.[Column]


You can use APPLY, but you don't need a subquery:
SELECT V.[Column], COUNT(*)
FROM T CROSS APPLY
(VALUES (T.ColumnA), (T.ColumnB), (T.ColumnC)
) v(Column)
GROUP BY V.[Column]


If values are distinct between columns you need UNION ALL:
SELECT "Column A" AS "Column", COUNT() AS "CountByValue"
FROM "MyTable"
GROUP BY "Column A"
UNION ALL
SELECT "Column B", COUNT()
FROM "MyTable"
GROUP BY "Column B"
UNION ALL
SELECT "Column C", COUNT()
FROM "MyTable"
GROUP BY "Column C"

Related

Case statement with four columns, i.e. attributes

I have a table with values "1", "0" or "". The table has four columns: p, q, r and s.
I need help creating a case statement that returns values when the attribute is equal to 1.
For ID 5 the case statement should return "p s".
For ID 14 the case statement should return "s".
For ID 33 the case statement should return 'p r s". And so on.
Do I need to come with a case statement that has every possible combination? Or is there a simpler way. Below is what I have come up with thus far.
case
when p = 1 and q =1 then "p q"
when p = 1 and r =1 then "p r"
when p = 1 and s =1 then "p s"
when r = 1 then r
when q = 1 then q
when r = 1 then r
when s = 1 then s
else ''
end

One solution could be this which uses a case for each attribute to return the correct value, surrounded by a trim to remove the trailing space.
with tbl(id, p, q, r, s) as (
select 5,1,0,0,1 from dual union all
select 14,0,0,0,1 from dual
)
select id,
trim(regexp_replace(case p when 1 then 'p' end ||
case q when 1 then 'q' end ||
case r when 1 then 'r' end ||
case s when 1 then 's' end, '(.)', '\1 '))
from tbl;
The real solution would be to fix the database design. This design technically violates Boyce-Codd 4th normal form in that it contains more than 1 independent attribute. The fact an ID "has" or "is part of" attribute p or q, etc should be split out. This design should be 3 tables, the main table with the ID, the lookup table containing info about attributes that the main ID could have (p, q, r or s) and the associative table that joins the two where appropriate (assuming an ID row could have more than one attribute and an attribute could belong to more than one ID), which is how to model a many-to-many relationship.
main_tbl main_attr attribute_lookup
ID col1 col2 main_id attr_id attr_id attr_desc
5 5 1 1 p
14 5 4 2 q
14 4 3 r
4 s
Then it would be simple to query this model to build your list, easy to maintain if an attribute description changes (only 1 place to change it), etc.
Select from it like this:
select m.ID, m.col1, listagg(al.attr_desc, ' ') within group (order by al.attr_desc) as attr_desc
from main_tbl m
join main_attr ma
on m.ID = ma.main_id
join attribute_lookup al
on ma.attr_id = al.attr_id
group by m.id, m.col1;

You can use concatenations with decode() functions
select id, decode(p,1,'p','')||decode(q,1,'q','')
||decode(r,1,'r','')||decode(s,1,'s','') as "String"
from t;
Demo
If you need spaces between letters, consider using :
with t(id,p,q,r,s) as
(
select 5,1,0,0,1 from dual union all
select 14,0,0,0,1 from dual union all
select 31,null,0,null,1 from dual union all
select 33,1,0,1,1 from dual
), t2 as
(
select id, decode(p,1,'p','')||decode(q,1,'q','')
||decode(r,1,'r','')||decode(s,1,'s','') as str
from t
), t3 as
(
select id, substr(str,level,1) as str, level as lvl
from t2
connect by level <= length(str)
and prior id = id
and prior sys_guid() is not null
)
select id, listagg(str,' ') within group (order by lvl) as "String"
from t3
group by id;
Demo

in my opinion, its a bad practice to use columns for relationships.
you should have two tables, one that's called arts and another that is called mapping art looks like this:
ID - ART
1 - p
2 - q
3 - r
4 - 2
...
and mapping maps your base-'ID's to your art-ids and looks like this
MYID - ARTID
5 - 1
5 - 4
afterwards, you should make use of oracles pivot operator. its more dynamically

Getting Number of Common Values from 2 comma-seperated strings

I have a table that contains comma-separated values in a column In Postgres.
ID PRODS
--------------------------------------
1 ,142,10,75,
2 ,142,87,63,
3 ,75,73,2,58,
4 ,142,2,
Now I want a query where I can give a comma-separated string and it will tell me the number of matches between the input string and the string present in the row.
For instance, for input value ',142,87,', I want the output like
ID PRODS No. of Match
------------------------------------------------------------------------
1 ,142,10,75, 1
2 ,142,87,63, 2
3 ,75,73,2,58, 0
4 ,142,2, 1

Try this:
SELECT
*,
ARRAY(
SELECT
*
FROM
unnest(string_to_array(trim(both ',' from prods), ','))
WHERE
unnest = ANY(string_to_array(',142,87,', ','))
)
FROM
prods_table;
Output is:
1 ,142,10,75, {142}
2 ,142,87,63, {142,87}
3 ,75,73,2,58, {}
4 ,142,2, {142}
Add the cardinality(anyarray) function to the last column to get just a number of matches.
And consider changing your database design.

Check This.
select T.*,
COALESCE(No_of_Match,'0')
from TT T Left join
(
select ID,count(ID) No_of_Match
from (
select ID,unnest(string_to_array(trim(t.prods, ','), ',')) A
from TT t)a
Where A in ('142','87')
group by ID
)B
On T.Id=b.id
Demo Here
OutPut

If you install the intarray extension, this gets quite easy:
select id, prods, cardinality(string_to_array(trim(prods, ','), ',')::int[] & array[142,87])
from bad_design;
Otherwise it's a bit more complicated:
select bd.id, bd.prods, m.matches
from bad_design bd
join lateral (
select bd.id, count(v.p) as matches
from unnest(string_to_array(trim(bd.prods, ','), ',')) as l(p)
left join (
values ('142'),('87') --<< these are your input values
) v(p) on l.p = v.p
group by bd.id
) m on m.id = bd.id
order by bd.id;
Online example: http://rextester.com/ZIYS97736
But you should really fix your data model.

with data as
(
select *,
unnest(string_to_array(trim(both ',' from prods), ',') ) as v
from myTable
),
counts as
(
select id, count(t) as c from data
left join
( select unnest(string_to_array(',142,87,', ',') ) as t) tmp on tmp.t = data.v
group by id
order by id
)
select t1.id, t1.prods, t2.c as "No. of Match"
from myTable t1
inner join counts t2 on t1.id = t2.id;

SQL query to get the count by applying group by

I want to get the below result:
source table :
Cnt A B
4 ABC YU/FGH
5 ABC YU/DFE
5 ABC KL
2 LKP BN/ER
4 JK RE
Result:
Cnt A B
9 ABC YU
5 ABC KL
2 LKP BN
4 JK RE
Here I want the count by grouping 'B' and want to display the 'B' record only till the special character (/)

Basically, you will have to filter out the all the characters after the "/" symbol and then apply a SUM and a GROUP BY. You can see this below. The inner query filters out the unwanted string and the outer query does the SUM and the GROUP BY :
SELECT SUM(t.Cnt), t.A, t.B
FROM (
SELECT Cnt,
A,
CASE
WHEN CHARINDEX('/', B) > 0 THEN SUBSTRING(B, 0, CHARINDEX('/', B))
ELSE B
END AS B
FROM #Tab
) t
GROUP BY t.A, t.B
ORDER BY t.A
You can see this working here -> http://rextester.com/IQJ79191
Hope this helps!!!

You can get your string till '/' by using SUBSTRING.
select
count(SUBSTRING(reverse(B),0,charindex('/',reverse(B)))),
A,
SUBSTRING(reverse(B),0,charindex('/',reverse(B)))
from source_table group by B;

Solution for Oracle - substr(B,0,instr(B,'/',1)-1) B
Put this both in select and groupby

I can suggest you to use a query like this:
select
sum(Cnt) Cnt,
A,
left(B, charindex('/',B+'/',0)-1) B -- Using `+'\'` will do the trick
from
t
group by
A,
left(B, charindex('/',B+'/',0)-1);

By using String and CharIndex Functions.
;WITH SourceTable(Cnt,A,B) AS
(
SELECT 4,'ABC','YU/FGH'UNION ALL
SELECT 5,'ABC','YU/DFE'UNION ALL
SELECT 5,'ABC','KL' UNION ALL
SELECT 2,'LKP','BN/ER' UNION ALL
SELECT 4,'JK','RE'
)
SELECT SUM(Cnt) AS Cnt,A,CASE WHEN CHARINDEX('/',B) = 0 THEN B
ELSE SUBSTRING(B,0,CHARINDEX('/',B)) END AS [B] FROM SourceTable
GROUP BY A,CASE WHEN CHARINDEX('/',B) = 0 THEN B
ELSE SUBSTRING(B,0,CHARINDEX('/',B)) END
ORDER BY Cnt DESC

Try this query --
SELECT SUM(Cnt) AS [COUNT]
,A
,CASE
WHEN CHARINDEX('/', B) > 0
THEN SUBSTRING(B, 1, (CHARINDEX('/', B) - 1))
ELSE B
END
FROM tblSample
GROUP BY A, B
ORDER BY A, B

SQL - Query column that does not exist

I have the following query where I am querying ISIN field.
SELECT Isin FROM FundPriceDetails
WHERE Isin IN
(
'ES06139009N6' , 'MAD',
'GB0002634946' , 'LSE',
'SG1L01001701' , 'SGX'
)
The second column does not exist but I wish to show it against ISIN values without inserting the row in my select query
How do I go about doing it ? A the moment I have only ISIN in my select statement. I need to create a anonymous column that contains the next column

Use a join:
SELECT x.*
FROM (SELECT 'ES06139009N6' AS lsin, 'MAD' AS col2 UNION ALL
SELECT 'GB0002634946', 'LSE' UNION ALL
SELECT 'SG1L01001701', 'SGX'
) x JOIN
FundPriceDetails fpd
ON fpd.lsin = x.lsin;

How can I Pivot a table in DB2? [duplicate]

This question already has answers here:
Pivoting in DB2
(3 answers)
Closed 5 years ago.
I have table A, below, where for each unique id, there are three codes with some value.
ID Code Value
---------------------
11 1 x
11 2 y
11 3 z
12 1 p
12 2 q
12 3 r
13 1 l
13 2 m
13 3 n
I have a second table B with format as below:
Id Code1_Val Code2_Val Code3_Val
Here there is just one row for each unique id. I want to populate this second table B from first table A for each id from the first table.
For the first table A above, the second table B should come out as:
Id Code1_Val Code2_Val Code3_Val
---------------------------------------------
11 x y z
12 p q r
13 l m n
How can I achieve this in a single SQL query?

select Id,
max(case when Code = '1' then Value end) as Code1_Val,
max(case when Code = '2' then Value end) as Code2_Val,
max(case when Code = '3' then Value end) as Code3_Val
from TABLEA
group by Id

SELECT Id,
max(DECODE(Code, 1, Value)) AS Code1_Val,
max(DECODE(Code, 2, Value)) AS Code2_Val,
max(DECODE(Code, 3, Value)) AS Code3_Val
FROM A
group by Id

If your version doesn't have DECODE(), you can also use this:
INSERT INTO B (id, code1_val, code2_val, code3_val)
WITH Ids (id) as (SELECT DISTINCT id
FROM A) -- Only to construct list of ids
SELECT Ids.id, a1.value, a2.value, a3.value
FROM Ids -- or substitute the actual id table
JOIN A a1
ON a1.id = ids.id
AND a1.code = 1
JOIN A a2
ON a2.id = ids.id
AND a2.code = 2
JOIN A a3
ON a3.id = ids.id
AND a3.code = 3
(Works on my V6R1 DB2 instance, and have an SQL Fiddle Example).

Here is a SQLFiddle example
insert into B (ID,Code1_Val,Code2_Val,Code3_Val)
select Id, max(V1),max(V2),max(V3) from
(
select ID,Value V1,'' V2,'' V3 from A where Code=1
union all
select ID,'' V1, Value V2,'' V3 from A where Code=2
union all
select ID,'' V1, '' V2,Value V3 from A where Code=3
) AG
group by ID

Here is the SQL Query:
insert into pivot_insert_table(id,code1_val,code2_val, code3_val)
select * from (select id,code,value from pivot_table)
pivot(max(value) for code in (1,2,3)) order by id ;

WITH Ids (id) as
(
SELECT DISTINCT id FROM A
)
SELECT Ids.id,
(select sub.value from A sub where Ids.id=sub.id and sub.code=1 fetch first rows only) Code1_Val,
(select sub.value from A sub where Ids.id=sub.id and sub.code=2 fetch first rows only) Code2_Val,
(select sub.value from A sub where Ids.id=sub.id and sub.code=3 fetch first rows only) Code3_Val
FROM Ids

You want to pivot your data. Since DB2 has no pivot function, yo can use Decode (basically a case statement.)
The syntax should be:
SELECT Id,
DECODE(Code, 1, Value) AS Code1_Val,
DECODE(Code, 2, Value) AS Code2_Val,
DECODE(Code, 3, Value) AS Code3_Val
FROM A