How to perform case in an oracle concat function ?
I want to concat number and a letter based on the number. ie if number is more than 1 than i have to append s else not.
I tried below query but its not working.
Select concat(count(*) , if count(*) > 1 then 's' else '')
from tablename
group by columnname;
In Oracle it is better to use || for concatenation, and there's no if but there are case expressions. I will show the solution with || as it is best practice, but if you must use concat you can do it as well. Also, Oracle will convert a number to a VARCHAR2 for you, but it is best to write your conversions explicitly.
select to_char(count(*)) || case when count(*) > 1 then 's' end from ....
NOTE - the default value of case is '' (same as NULL in Oracle), so I didn't need to write more.
Related
I am trying to come up with an equivalent of the below Oracle statement in Snowflake. This would check if the different parts of the string separated by '.' matches the number of characters in the REGEXP_LIKE expression. I have come up with a rudimentary version to perform the check in Snowflake but I am sure there's a better and cleaner way to do it. I am looking to come up with a one-liner regular expression check in Snowflake similar to Oracle. Appreciate your help!
-- Oracle
SELECT -- would return True
CASE
WHEN REGEXP_LIKE('AB.XYX.12.34.5670.89', '^\w{2}\.\w{3}\.\w{2}') THEN 'True'
ELSE NULL
END AS abc
FROM DUAL
-- Snowflake
SELECT -- would return True
REGEXP_LIKE(SPLIT_PART('AB.XYX.12.34.5670.89', '.', 1), '[A-Z0-9]{2}') AND
REGEXP_LIKE(SPLIT_PART('AB.XYX.12.34.5670.89', '.', 2), '[A-Z0-9]{3}') AND
REGEXP_LIKE(SPLIT_PART('AB.XYX.12.34.5670.89', '.', 3), '[A-Z0-9]{2}') AS abc
You need to add a .* at the end as the REGEXP_LIKE adds explicit ^ && $ to string:
The function implicitly anchors a pattern at both ends (i.e. '' automatically becomes '^$', and 'ABC' automatically becomes '^ABC$'). To match any string starting with ABC, the pattern would be 'ABC.*'.
select
column1 as str,
REGEXP_LIKE(str, '\\w{2}\\.\\w{3}\\.\\w{2}.*') as oracle_way
FROM VALUES
('AB.XYX.12.34.5670.89')
;
gives:
STR
ORACLE_WAY
AB.XYX.12.34.5670.89
TRUE
Or in the context of your question:
SELECT IFF(REGEXP_LIKE('AB.XYX.12.34.5670.89', '\\w{2}\\.\\w{3}\\.\\w{2}.*'), 'True', null) AS abc;
Your use of \w seems to suggest you don't need delimited strings to be strictly [A-Z0-9] since word characters allow underscore and period. If all bets were off and the only requirement was to have . at 3rd, 7th and 10th position, you could have used like this way.
select 'AB.XGH.12.34.5670.89' like '__.___.__.%' ;
I need help
i have records 123,456,789 in rows when i am execute like
this one is working
select * from table1 where num1 in('123','456')
but when i am execute
select * from table1 where num1 in(select value from table2)
no resultset found - why?
Check the DataType varchare2 or Number
try
select * from table1 where num1 in(select to_char(value) from table2)
Storing comma separated values could be the cause of problem.
You can try using regexp_substr to split comma.
First and foremost, an important thing to remember: Do not store numbers in character datatypes. Use NUMBER or INTEGER. Secondly, always prefer VARCHAR2 datatype over CHAR if you wish to store characters > 1.
You said in one of your comments that num1 column is of type char(4). The problem with CHAR datatype is that If your string is 3 characters wide, it stores the record by adding extra 1 space character to make it 4 characters. VARCHAR2 only stores as many characters as you pass while inserting/updating and are not blank padded.
To verify that you may run select length(any_char_col) from t;
Coming to your problem, the IN condition is never satisfied because what's actually being compared is
WHERE 'abc ' = 'abc' - Note the extra space in left side operator.
To fix this, one good option is to pad the right side expression with as many spaces as required to do the right comparison.The function RPAD( string1, padded_length [, pad_string] ) could be used for this purpose.So, your query should look something like this.
select * from table1 where num1 IN (select rpad(value,4) from table2);
This will likely utilise an index on the column num1 if it exists.
The other one is to use RTRIM on LHS, which is only useful if there's a function based index on RTRIM(num1)
select * from table1 where RTRIM(num1) in(select value from table2);
So, the takeaway from all these examples is always use NUMBER types to store numbers and prefer VARCHAR2 over CHAR for strings.
See Demo to fully understand what's happening.
EDIT : It seems You are storing comma separated numbers.You could do something like this.
SELECT *
FROM table1 t1
WHERE EXISTS (
SELECT 1
FROM table2 t2
WHERE ',' ||t2.value|| ',' LIKE '%,' || rtrim(t1.num1) || ',%'
);
See Demo2
Storing comma separated values are bound to cause problems, better change it.
Let me tell you first,
You have stored values in table2 which is comma seperated.
So, how could you match your data with table1 and table2.
Its not Possible.
That's why you did not get any values in result set.
I found the Solution using string array
SELECT T.* FROM TABLE1 T,
(SELECT TRIM(VALUE)AS VAL FROM TABLE2)TABLE2
WHERE
TRIM(NUM1) IN (SELECT COLUMN_VALUE FROM TABLE(FUNC_GETSTRING_ARRAY(TABLE2.VAL)))
thanks
Can we use more than one column in a single WHEN clause while using CASE in oracle?
A CASE expression can use more than one column in its logic, e.g.
CASE WHEN col1 > val1 AND col2 > val2 THEN 1 ELSE 0 END
But a CASE expression must return a single scalar value.
no you cant, but you can use multi when clause statement like this:
select
case when .... end col_a,
case when .... end col_b
from
xxxx
Of course you can. For example:
select ...
from emp
where case when bonus is null then salary else salary + bonus end > 4000
Here emp is a table, and bonus and salary are two of the columns in that table. The same WHERE clause can be expressed more simply, but regardless of reformulation, it will refer to both columns. (And there will be a CASE of some sort somewhere - NVL and COALESCE are CASE expressions with a different syntax.)
In Oracle, usually, SQL functions that should return true/false return 1/0 because the BOOLEAN data type only exists in PL/SQL blocks.
For example with Oracle Text, you must not forget the > 0 in SELECT * FROM bartbl WHERE CONTAINS(foocol, 'sometext') > 0. Otherwise you get ORA-00920 invalid relational operator.
However, it seems that REGEXP_LIKE behaves like a true boolean: you can do SELECT * FROM bartbl WHERE REGEXP_LIKE(foocol, 'sometext') and it works.
So I would like to know why this is the case and if there is a possibility for me to write some functions like this?
Once upon a time, there was no boolean requirement in ANSI SQL (not sure if that requirement exists in latest standards?), and Oracle tends to do their own thing sometimes ;) But, personally I don't see the issue in using Y/N or 1/0.
Anyway, REGEXP_LIKE is really a type of filter (can reduce the number of rows returned), not the same as a typical function (which will return a value (or null) for each row it processes). But good thing is that if you really want to mimic the filter functionality, you can use REGEXP_LIKE with your own function. For example:
create or replace function is_big_number(i_num in number)
return varchar2
as
begin
if (i_num >= 1000000) then
return 'Y';
end if;
return 'N';
end;
with x as (
select 50000 as num from dual
union all
select 1000000 as num from dual
union all
select 3 as num from dual
)
select num, is_big_number(num)
from x
-- this is a filter, not a typical "function"
where
regexp_like(is_big_number(num), 'Y');
Output:
NUM IS_BIG_NUMBER(NUM)
1000000 "Y"
Hope that helps.
Oracle's built in functions are special, you can't write one like this yourself. I don't know why though
Is it possible to use SELECT result as DECODE parameters when this SELECT returns only one record with prepared string?
For example:
SELECT replace(replace(serialized_data)..)..) as result FROM table
Returns following result in ONE ROW:
0,'label0',1,'label1',2,'label2'
But when I put this to DECODE it's being interpreted as ONE PARAMETER.
Is there possiblity to convert this result "string" to "pure" sql code? ;)
Thanks for any help.
You could kind of replicate decode by use of instr and substr. An example below (which could probably be tidied up considerably but works):
select DTXT
,Nvl(
Substr(
DTXT
,Instr(DTXT, SEARCHTXT || VALMTCH)
+ Length(SEARCHTXT || VALMTCH)
, Instr(DTXT, VALSEP, Instr(DTXT, SEARCHTXT || VALMTCH))
- Instr(DTXT, SEARCHTXT || VALMTCH)
- Length(SEARCHTXT || VALMTCH))
,CASEOTHER)
as TXTMATCH
from (select '0=BLACK;1=GREEN;2=YELLOW;' as DTXT
,'1' as SEARCHTXT
,';' as VALSEP
,'=' as VALMTCH
,'OTHER' as CASEOTHER
from Dual)
You do need to have a semi-colon (VALSEP) at the end of the text though to ensure you can find the last value (though it's possible to work around that if I looked into it further).
list_agg or wm_concat depending on version of oracle.
http://docs.oracle.com/cd/E14072_01/server.112/e10592/functions087.htm
You can use dynamic SQL:
declare
DECTXT varchar2(4000);
begin
select replace(replace(serialized_data)..)..) as result into dectxt from table;
execute immediate 'select decode(col1,' || DECTXT || ') from tab1';
end;
This is just a quick example, not showing any output, etc.