Postgresql parse string values to integers - postgresql

Is there a way in Postgres I can parse string values to integers? Basically I'm trying to query one table (let's call it table_one) using values from another table (table_two) in a character varying column.
Say SELECT char_column FROM table_two results in "2,4,6,8", I'd like to use this result in a second query as;
SELECT column FROM table_one WHERE some_id IN (2,4,6,8)
How can I get the string "2,4,6,8" to values 2,4,6,8 so as to be able to use it in the second query?
I've tried casting and to_number functions to no success.


SELECT column
FROM table
WHERE other_column = ANY(string_to_array('2,4,6,8', ',')::INT[])


Please try this:
SELECT column FROM table WHERE other_column IN (
SELECT NULLIF(i,'')::int
FROM regexp_split_to_tables('2,4,6,8',',') t(i)
)
Explanation:
The part regexp_split_to_tables('2,4,6,8',',') will split the string into a table. Then you cast it into integer.
Hopefully it will help you.

Related

Db2 convert rows to columns

I need the below results ..
Table :
Order postcode qnty
123 2234 1
Expected result:
Order 123
Postcode 2234
Qnty 1
SQL server:
Select pvt.element_name
,pvt.element_value(select order.postcode
from table name)up
unpivot (element_value for element_name in(order,postcode) as Pvt
How to achieve this in db2?

Db2 for IBM i doesn't have a built-in unpviot function.. AFAIK, it's not available on any Db2 platofrm...unless it's been added recently.
The straight forward method
select 'ORDER' as key, order as value
from mytable
UNION ALL
select 'POSTCODE', postcode
from mytable
UNION ALL
select 'QNTY', char(qnty)
from mytable;
A better performing method is to do a cross join between the source table and a correlated VALUES of as many rows as columns that need to be unpivoted.
select
Key, value
from mytable T,
lateral (values ('ORDER', t.order)
, ('POSTCODE', t.postcode)
, ('QNQTY', varchar(t.qnty))
) as unpivot(key, value);
However, you'll need to know ahead of time what the values you're unpivoting on.
If you don't know the values, there are some ways to unpivot with the XMLTABLE (possibly JSON_TABLE) that might work. I've never used them, and I'm out of time to spend answering this question. You can find some examples via google.

I have created a stored procedure for LUW that rotate a table:
https://github.com/angoca/db2tools/blob/master/pivot.sql
You just need to call the stored procedure by passing the tablename as parameter, and it will return a cursor with the headers of the column in the first column.

Selecting a row by searching a specific value in an Array column

We have a table where one of the columns is an array. I need to select a row or many rows as long as my search value matches their values using ILIKE. My problem is that I need to search the values of an array column as well. I tried using ANY but the value needs to be exact to select a row. I need something similar to ILIKE but for that array column.
Thank you in advance.

Use unnest function:
SELECT x.value
FROM my_table t, unnest(t.my_array_column) as x(value)
WHERE x.value ILIKE 'foo'
Once your question is also tagged elixir, for converting this to Ecto use Ecto.Query.API.fragment/1 for the select condition and Ecto.Query.API.ilike/2 for match.

Ignore specific rows from a table

I have a table with data like this:
ND
10212121
10232323
10212323
212526
295652
232565
I would like make a select to all ND from this table excluding these starting with 10...using openquery to a oracle database.
Regards

In the following query I check the first two characters of the ND column and compare against 10 to see if they be equal. You did not mention whether or not ND is a numeric type, so I added a cast to varchar2 so that the substring will work.
SELECT ND
FROM yourTable
WHERE SUBSTR(CAST(ND AS varchar2(30)), 1, 2) <> '10'

sort varchar column with alphanumeric data in Redshift

I have a column in redshift database which contains values like 11E, 11N, 11W,12W,12E,12S,1S,2E. Need to sort column like 1S,2E,11E,11N,11W,12E,12S,12W.

you need to separate the numbers from the characters.
try this order
SELECT a FROM example
ORDER BY
convert(integer,case when length(a)= 2 then left(a,1) else left(a,2) end),
right(a,1)

Hive: How to do a SELECT query to output a unique primary key using HiveQL?

I have the following schema dataset which i want to transform into a table that can be exported to SQL. I am using HIVE. Input as follows
call_id,stat1,stat2,stat3
1,a,b,c,
2,x,y,z,
3,d,e,f,
1,j,k,l,
The output table needs to have call_id as its primary key so it needs to be unique. The output schema should be
call_id,stat2,stat3,
1,b,c, or (1,k,l)
2,y,z,
3,e,f,
The problem is that when i use the keyword DISTINCT in the HIVE query, the DISTINCT applies to the all the colums combined. I want to apply the DISTINCT operation only to the call_id. Something on the lines of
SELECT DISTINCT(call_id), stat2,stat3 from intable;
However this is not valid in HIVE(I am not well-versed in SQL either).
The only legal query seems to be
SELECT DISTINCT call_id, stat2,stat3 from intable;
But this returns multiple rows with same call_id as the other columns are different and the row on the whole is distinct.
NOTE: There is no arithmetic relation between a,b,c,x,y,z, etc. So any trick of averaging or summing is not viable.
Any ideas how i can do this?

One quick idea,not the best one, but will do the work-
hive>create table temp1(a int,b string);
hive>insert overwrite table temp1
select call_id,max(concat(stat1,'|',stat2,'|',stat3)) from intable group by call_id;
hive>insert overwrite table intable
select a,split(b,'|')[0],split(b,'|')[1],split(b,'|')[2] from temp1;

,,I want to apply the DISTINCT operation only to the call_id"
But how will then Hive know which row to eliminate?
Without knowing the amount of data / size of the stat fields you have, the following query can the job:
select distinct i1.call_id, i1.stat2, i1.stat3 from (
select call_id, MIN(concat(stat1, stat2, stat3)) as smin
from intable group by call_id
) i2 join intable i1 on i1.call_id = i2.call_id
AND concat(i1.stat1, i1.stat2, i1.stat3) = i2.smin;