Conditionally concatenating fields in Oracle - sql

What I need to do is to concatenate 4 fields in Oracle SQL Developer. The fields are:
Network, Network2, Network3, Network4
However, sometimes not all of the fields are filled in. This would always happen in sequence; it would never be just Network3 that's empty, it's either they fill in the first one only, the first 2 only, etc...
So, how can I write a Select statement that will ignore any fields that are NULL? I need the end result to look like:
Select Network, Network2, Network3, Network4 as Defect
and it should show Defect as something like "ON1, ON2, ON3, ON4" all in one field. But if only the first 2 are filled in, I don't want it to look like, "ON1, ON2, , , ".

Use NVL2(v, valueIfNotNull, valueIfNull)
SELECT
Network
|| nvl2(Network2, ', ' || Network2, '')
|| nvl2(Network3, ', ' || Network3, '')
|| nvl2(Network4, ', ' || Network4, '') AS Defect
FROM my_table

Use the CONCATENATE || operator and COALESCE() function:
SELECT Network
|| COALESCE(' - ' || Network2, '')
|| COALESCE(' - ' || Network3, '')
|| COALESCE(' - ' || Network4, '')
as Defect

Related

regexp_substr for getting correct result

I was trying to use regexp_substr to get each correct column name from a column list string.
The query is like:
select regexp_substr(v_keep, '(^|[(,) ]*)' || r.column_name || '($|[(,) ]+)', 1, 1, 'i')
from dual;
But the result is not correct.
The v_keep can be any column name list like abc, abc_abc, abc1 or (abc, abc_abc, abc1).
The r.column_name can be like abc or ab.
- If the input v_keep is (abc, abc_abc, abc1) and the r.column_name is
ab, it will return null.
- If the input v_keep is (abc, abc_abc, abc1) and the r.column_name is
abc, it will return the column name just abc.
Can anyone help me to fix it by just modify the pattern inside the regexp_substr ?
Why not just use a case and like?
select (case when replace(replace(v_keep, '(', ','), '(', ',')) like '%,' || r.column_name || ',%'
then r.column_name
end)
I don't recommend storing lists in a comma-delimited string, but if you are, this is one way to identify individual elements of the list.
It's pretty simple, you just need to add a subexpression so you can pull out the part of the string you want. (A subexpression is a section of the regexp in parentheses.) In this case the last argument is 2, because you want the part of the match that corresponds to the second group of parentheses.
regexp_substr(v_keep, '(^|[(,) ]*)(' || r.column_name || ')($|[(,) ]+)', 1, 1, 'i', 2)
Gordon's solution will have better performance, though.
Edit: working example -
with testdata as (select '(abc, abc_abc, abc1)' as v_keep, 'abc' as column_name from dual)
select regexp_substr(v_keep, '(^|[(,) ]*)(' || r.column_name || ')($|[(,) ]+)', 1, 1, 'i', 2)
from testdata r;
Since this is PL/SQL code to see if a value is in a string, try this which avoids the overhead of hitting the database, and calling REGEXP. Just keep it straight SQL. I hate the nested REPLACE calls but I was trying to avoid using REGEXP_REPLACE although it could be done in one call if you did use it.
set serveroutput on;
set feedback off;
declare
v_keep varchar2(50) := '(abc, abc_abc, abc1)';
compare varchar2(10) := 'abc_';
begin
if instr(',' || replace(replace(replace(v_keep, ' '), '('), ')') || ',', ',' || compare || ',') > 0 then
dbms_output.put_line('Column ''' || compare ||''' IS in the keep list');
else
dbms_output.put_line('Column ''' || compare ||''' IS NOT in the keep list');
end if;
end;

How to put text into SQL select statement

I have the following problem.
We are using ORACLE Apex Application Express. We have database with some information inside.
I need to write a SQL select that shows information but I have to follow one rule
"Price for 'row_name' is 'row_price' usd"
Where the row_name is the name of product and the row_price is sum(price1+price2).
You can use the || operator to concatinate strings:
SELECT 'Price for ' ||
prod_name ||
' is ' ||
TO_CHAR(delprice + sellprice) ||
' usd'
FROM my_table

Having issues with NVL in select statement

I need to display a vendor address which is composed of three concatenated fields such as address, state, zip. My only issue is that one of the vendors has a null value for his address so it reads NULL STATE ZIP.
I tried:
SELECT vendor_name, NVL(vendor_address1, ' ') || ' ' || vendor_state || ' ' || VENDOR_ZIP_CODE AS "Complete Address"
from ap.vendors;
As well as
SELECT vendor_name, NVL(to_char(vendor_address1), ' ') || ' ' || vendor_state || ' ' || VENDOR_ZIP_CODE AS "Complete Address"
from ap.vendors;
But the null is always displayed as NULL.
Not sure what my options are at this point.
Nevermind, I figured out the issue, or at least I think I did. Null wasn't a type but a string, so when I used the replace function it worked.

Format Column Headers during Pipe Delimited Concatenation (Oracle SQL)

Overview: I am tasked with providing a data extract from an Oracle database as a pipe-delimited output text file. I will be using SQLPlus to do this on the server where the data lives. Ordinarily, this task is not beyond my experience, but this time, the business desires column headers to be present.
Consider the following five columns that I need to output:
SELECT
a.USER_NAME || '|'
|| a.LAST_NAME || '|'
|| a.FIRST_NAME || '|'
|| b.PRODUCT_PURCHASED || '|'
|| c.DATEPURCHASED
FROM ...
WHERE ... ;
This SQL works fine, where the output looks like:
omnusruthius|ruthius|omnus|stackoverflow_prod|19-APR-16
However, the business wants it to look like:
USER_NM|LAST|FIRST|PROD|EFFECTIVE_DATE
omnusruthius|ruthius|omnus|stackoverflow_prod|19-APR-16
Problem: So the objective here is essentially to output the first row with custom-named column headers (aliases), as shown above. So my first approach was to try something like:
SELECT
a.USER_NAME AS USER_NM || '|'
|| a.LAST_NAME AS LAST || '|'
|| a.FIRST_NAME AS FIRST || '|'
|| b.PRODUCT_PURCHASED AS PROD || '|'
|| c.DATEPURCHASED AS EFFECTIVE_DATE
FROM ...
WHERE ...
Unfortunately, I receive:
ORA-00923: FROM keyword not found where expected
I'm not sure how that would help anyway, as the original SQL output without aliases does not show column headers in the first row anyway. Remember, this is through the command line (SQLPlus), not Toad or some other RDMS.
So then I tried:
SELECT
'USER_NM', 'LAST', 'FIRST', 'PROD', 'EFFECTIVE_DATE' FROM DUAL
UNION ALL
SELECT
a.USER_NAME || '|'
|| a.LAST_NAME || '|'
|| a.FIRST_NAME || '|'
|| b.PRODUCT_PURCHASED || '|'
|| c.DATEPURCHASED
FROM ...
WHERE ...
Which gives the following error:
ORA-01789: query block has incorrect number of result columns
I feel so close to the solution, what am I missing here? Any help will be appreciated!
Edit: Just a note to a future reader, both answers here will help you solve this problem, but upon further tweaking, I realize we've all been overthinking the solution. I'm not going to propose a new solution as the change is trivial, but consider doing the following instead:
SELECT 'USER_NM|LAST|FIRST|PROD|EFFECTIVE_DATE' FROM DUAL;
SELECT a.USER_NAME AS USER_NM || '|'
|| a.LAST_NAME AS LAST || '|'
|| a.FIRST_NAME AS FIRST || '|'
|| b.PRODUCT_PURCHASED AS PROD || '|'
|| c.DATEPURCHASED AS EFFECTIVE_DATE
FROM ...
WHERE ...
ORDER BY ... ;
The key here is the use of the semicolons in SQL*Plus. That first SELECT statement is completely independent from the second; no UNION is necessary as the output of the first query is automatically displayed immediately before the output of the second query. Both can have their own rules, which is especially convenient if your latter query is much more complicated. I can confirm the above query is working, and I'm surprised it took me that long to make that realization...
When concatenating make sure the header is a single string. Because you are concatenating the values in columns to be on one row.
If comma separation is used, as you have it in the question, the result block should also have 5 columns,which is not the case.
SELECT
'USER_NM|LAST|FIRST|PROD|EFFECTIVE_DATE' FROM DUAL
UNION ALL
SELECT
a.USER_NAME || '|'
|| a.LAST_NAME || '|'
|| a.FIRST_NAME || '|'
|| b.PRODUCT_PURCHASED || '|'
|| c.DATEPURCHASED
FROM ...
WHERE ...
Edit: The columns can also be sorted.
SELECT 'USER_NM|LAST|FIRST|PROD|EFFECTIVE_DATE' FROM DUAL
UNION ALL
SELECT * FROM (
SELECT
a.USER_NAME || '|'
|| a.LAST_NAME || '|'
|| a.FIRST_NAME || '|'
|| b.PRODUCT_PURCHASED || '|'
|| c.DATEPURCHASED
FROM ...
WHERE ...
ORDER BY DATEPURCHASED) --add any other columns needed
Since you tagged the question with SQL*Plus, you can use the PROMPT command to generate the header, which avoids complications ordering the results with a union:
PROMPT USER_NM|LAST|FIRST|PROD|EFFECTIVE_DATE
SELECT
a.USER_NAME AS USER_NM || '|'
|| a.LAST_NAME AS LAST || '|'
|| a.FIRST_NAME AS FIRST || '|'
|| b.PRODUCT_PURCHASED AS PROD || '|'
|| c.DATEPURCHASED AS EFFECTIVE_DATE
FROM ...
WHERE ...
ORDER BY ...
That takes the headings out of the SQL and into the client realm, where it arguably belongs. This also works in SQL Developer, and other clients may be able to do something similar. It won't work if you run the query on its own from another client, or over JDBC, or whatever; but then whatever is running the query can (and maybe should) provide the header in that case too.
If you aren't already, you could also consider doing SET HEADING OFF or SET PAGESIZE 0 to suppress the column headings from the query itself (though from what you said you're already doing that); and possibly SET EMBED OFF, though I don't think that's needed unless you do a separate query to generate the header line.

Concatenate string in Oracle SQL? (wm-concat)

I've got some SQL that I'd like to format correctly for a mailout (generated directly from SQL - don't ask!). The code is as follows:
SELECT wm_concat('<br>• ' || FIELD1 || ' ' || FIELD2 || ' : ' || FIELD 3 || ' text') AS "Team"
Okay, so this kinda works - but it places a comma at the end of each line. Silly question, and possibly quite trivial, but is there anyway at all to remove the comma please? I think it's being added by the wm_concat function
Thanks
Yes the WM_CONCAT function puts a comma between each value it concatenates.
If there are no commas in your data you could do this:
SELECT replace (wm_concat('<br>• ' || FIELD1 || ' ' || FIELD2 || ' : '
|| FIELD 3 || ' text'),
',', null) AS "Team"
If you are on 11G you can use the new LISTAGG function instead:
SELECT LISTAGG ('<br>• ' || FIELD1 || ' ' || FIELD2 || ' : '
|| FIELD 3 || ' text')
WITHIN GROUP (ORDER BY <something>) AS "Team"
That will produce a result without commas.
Just trim the string for trailing commas:
RTRIM( wm_concat(...), ',' )
Oracle 10g provides a very convenient function wm_concat used to solve line reclassified demand, very easy to use this function, but the function provides only ',' this kind of delimiter.
In fact, as long as some simple conversion you can use other delimiters separated, the first thought is replace function
with t as( select 'a' x from dual union select 'b' from dual )
select replace(wm_concat(x),',','-') from t;
But taking into account the string itself may contain ',' character, use the above SQL will lead to erroneous results, but also made some changes to the above SQL.
with t as( select 'a' x from dual union select 'b' y from dual)
select substr(replace(wm_concat('%'||x),',%','-'),2) from t;
In the above SQL by a '%' as a separator, and then replace the '%' to remove the error. The program assumes that the string does not exist within the '%' string to replace the '%' in the SQL can also use other special characters.
Source: http://www.databaseskill.com/3400944/
You can create your own aggregate functions in Oracle and use those to aggregate strings.
Or use the StrAgg function written by Tom Kyte: http://www.sqlsnippets.com/en/topic-11591.html
SELECT StrAgg('<br>• ' || FIELD1 || ' ' || FIELD2 || ' : ' || FIELD 3 || ' text') AS "Team"
FROM Abc