How do you split a string value in DB2?
For example, given the value:
CHG-FFH.
I want to split on the dash (-), which would result in two values:
CHG
FFH.
I tried using split function but it is not a function in DB2.
Any help will be appreciated.
Short answer:
You need to find the position of the delimiter, and then substring using it as the starting point, and a calculated length.
SELECT
SUBSTR('CHG-FFH', 1, LOCATE('-','CHG-FFH')-1) as FIRST_PART
, SUBSTR('CHG-FFH', LOCATE('-','CHG-FFH')+1) as SECOND_PART
FROM SYSIBM.SYSDUMMY1;
BONUS! If you do this often, create a user defined function to do it dynamically. Here's an example in a DB fiddle.
CREATE FUNCTION SPLITTER (input VARCHAR(4000), delimiter CHAR, part_number INTEGER)
RETURNS VARCHAR(4000)
LANGUAGE SQL
READS SQL DATA
NO EXTERNAL ACTION
DETERMINISTIC
RETURN
with pos_info (first_pos, length) as (
select
case when part_number = 1 then 0
else LOCATE_IN_STRING(input, delimiter,1, part_number-1, OCTETS)
end as first_pos,
case when part_number = 1 then LOCATE_IN_STRING(input, delimiter,1, part_number, OCTETS) - 1
when LOCATE_IN_STRING(input, delimiter,1, part_number, OCTETS) = 0
and LOCATE_IN_STRING(input, delimiter,1, part_number-1, OCTETS) = 0
then 0
when LOCATE_IN_STRING(input, delimiter,1, part_number, OCTETS) = 0
then length(input) - LOCATE_IN_STRING(input, '-',1, part_number - 1, OCTETS)
else LOCATE_IN_STRING(input, delimiter,1, part_number, OCTETS) - LOCATE_IN_STRING(input, delimiter,1, part_number-1, OCTETS) - 1
end as length
from sysibm.sysdummy1
)
select
substr(input, first_pos+1,length) as part
from pos_info;
Alternatively, you can see a different approach here at this answer: Split a VARCHAR in DB2 to retrieve a value inside.
Long answer:
DB2, along with other relational databases do not provide a single function to accomplish this.
The reason is likely that it's not an implicitly scalar function. If your string had more than one dash in it, would you want to split it into three parts? Four? So the first step is to note if your data is determinate - if it has a specific number of components that you want to split apart. In your example, you have two, so I'll start with that assumption, and then afterwards comment on how you would deal other situations.
Scenario: A string value with two components separated by a delimiter
With only two parts, you need to find the position of the delimiter, and then substring before and after it by using the position before and after it in a substring function.
LOCATE('-','CHG-FFH')
NOTE: DB2 provides two functions which can be used for this: POSITION (or POSSTR), and LOCATE (or LOCATE_IN_STRING). LOCATE is a bit more powerful because it allows you to specify a start position, which would be helpful if you had more than one delimiter.
For the first part, start your substring at position 1, up to the character before the delimiter (delimiter position - 1):
SUBSTR('CHG-FFH', 1,LOCATE('-','CHG-FFH')-1) as FIRST_PART
For the second part, start your substring at the position after delimiter index (delimiter position + 1), and get the rest of the String:
SUBSTR('CHG-FFH', LOCATE('-','CHG-FFH')+1) as SECOND_PART
Final Result:
SELECT
SUBSTR('CHG-FFH', 1,LOCATE('-','CHG-FFH')-1) as FIRST_PART
, SUBSTR('CHG-FFH', LOCATE('-','CHG-FFH')+1) as SECOND_PART
FROM SYSIBM.SYSDUMMY1;
Scenario: A string value with three components separated by a delimiter
Use the same concepts as the first scenario, but you have to determine the index of the second delimiter. Use the index of the first delimiter to specify a starting point: Note that LOCATE allows specifying a start position:
>>-LOCATE(search-string,source-string-+--------+-+--------------------+-)-><
'-,start-' '-,--+-CODEUNITS16-+-'
+-CODEUNITS32-+
'-OCTETS------'
Finding the second delimiter:
Use the position of the first delimiter as the starting point for finding the second delimiter.
LOCATE('-','CHG-FFH-EEE', LOCATE('-','CHG-FFH-EEE')+1)
Use that as a SUBSTR point for the second and third values, and you're all set. Note: For the second value, you have to use both of the delimiter locations to substring the value.
Final Result:
SELECT
SUBSTR('CHG-FFH-EEE', 1,LOCATE('-','CHG-FFH-EEE')-1) as FIRST_PART
, SUBSTR('CHG-FFH-EEE', LOCATE('-','CHG-FFH-EEE')+1, LOCATE('-','CHG-FFH-EEE', LOCATE('-','CHG-FFH-EEE'))-1) as SECOND_PART
, SUBSTR('CHG-FFH-EEE', LOCATE('-','CHG-FFH-EEE', LOCATE('-','CHG-FFH-EEE')+1)+1) as THIRD_PART
FROM SYSIBM.SYSDUMMY1;
You can see this strategy would get out of hand for a greater number of delimiters in your String.
Scenario: Indeterminate number of delimiters
This is a tricky problem that is best approached with a Stored Procedure. Think through things like: How do you want the parsed data to come out of the algorithm, how will you access the data? Arrays are not a native type in SQL, but they are in Stored Procedures, so what will you do with the array when you've parsed all the pieces out of your String?
One way to approach this scenario is answered here:
This is what i tried and it fetched me effective result. Hence sharing with all.
select column_name, substr(column_name,1,locate('-',column_name)-1),
substr(column_name,locate('-',column_name)+1,
length(substr(column_name,locate('-',column_name)+1))) from
table_name where column_name is not null and column_name!=''
and column_name like '%-%'
The reason of so late answer is to show much more simple and universal way to achieve the goal. It's based on functions using regular expressions available even at the time, when the question was asked.
SELECT
COL
-- since 9.7 (2009)
, xmlcast(xmlquery('fn:tokenize($s, "-")[2]' passing COL as "s") as varchar(20)) as one
-- since 11.1
, REGEXP_SUBSTR(COL, '([^-]*)-?', 1, 2, '', 1) as two
FROM (VALUES 'CHG-FFH.', 'ABC-DEF-GH') TAB (COL);
The result is:
|COL |ONE |TWO |
|----------|--------------------|----------|
|CHG-FFH. |FFH. |FFH. |
|ABC-DEF-GH|DEF |DEF |
-- since 9.7 (2009)
SELECT TAB.COL, TOK.SEQ, TOK.TOKEN
FROM
(VALUES 'CHG-FFH.', 'ABC-DEF-GH') TAB (COL)
, XMLTABLE
(
'for $id in tokenize($s, "-") return <i>{string($id)}</i>' PASSING TAB.COL AS "s"
COLUMNS
SEQ FOR ORDINALITY
, TOKEN VARCHAR(20) PATH '.'
) TOK
ORDER BY TAB.COL, TOK.SEQ;
The result is:
|COL |SEQ |TOKEN |
|----------|--------------------|--------------------|
|ABC-DEF-GH|1 |ABC |
|ABC-DEF-GH|2 |DEF |
|ABC-DEF-GH|3 |GH |
|CHG-FFH. |1 |CHG |
|CHG-FFH. |2 |FFH. |
Try this statement:
select substr(your_value, 1,3), substr(your_value, 4, 3) from your_table
This answer is not totally different, but it impements LOCATE_IN_STRING in a more flexible way which is useful, for example, if you have restrictions not to use functions.
To get the nth string delimited by the character '-' as in your example:
SUBSTR(THESTRING, LOCATE_IN_STRING(THESTRING, '-', 1, n - 1) + 1,
LOCATE_IN_STRING(THESTRING||'-', '-', 1, n) - LOCATE_IN_STRING(THESTRING, '-', 1, n - 1) - 1)
If you replace each occurrence of n by the column number you want, this construct will return the nth column's contents.
Some explanation:
The length of the string to be extracted by SUBSTR is calcluated from the difference between the occurrence of the nth and the (n + 1)th delimiter character (- in this case). Note that the (n + 1)th delimiter position is calculated from THESTRING plus an extra delimiter attached to its end to account for the case when we look for the last column and THESTRING does not end in a delimiter.
I know this is old post.. but thought following may help others.
I used following approach to split the given string.
SELECT TRIM(ITEM) AS ITEM FROM TABLE(<LIB1>.SF_SPLIT(I_INPUTLIST=>'AA|BB|CC|DD|EE|EE|FF', I_DELIMITER=>'|')) AS T;
SF_SPLIT is the User defined SQL function and below is definition:
CREATE OR REPLACE FUNCTION <LIB1>.SF_SPLIT(
I_INPUTLIST VARCHAR(8000)
, I_DELIMITER VARCHAR(3)
)
RETURNS TABLE (ITEM VARCHAR(8000))
LANGUAGE SQL
RETURN
WITH R1 (ITEM, REMINDER) AS
(SELECT SUBSTR(I_INPUTLIST, 1, LOCATE(I_DELIMITER, I_INPUTLIST)-1) AS ITEM,
SUBSTR(I_INPUTLIST, LOCATE(I_DELIMITER, I_INPUTLIST)+1, LENGTH(I_INPUTLIST)) REMINDER
FROM SYSIBM.SYSDUMMY1
UNION ALL
SELECT SUBSTR(REMINDER, 1, LOCATE(I_DELIMITER, REMINDER)-1) AS ITEM,
SUBSTR(REMINDER, LOCATE(I_DELIMITER, REMINDER)+1, LENGTH(REMINDER)) REMINDER
FROM R1 WHERE LOCATE(I_DELIMITER, REMINDER) > 0
UNION ALL
SELECT SUBSTR(REMINDER, LOCATE(I_DELIMITER, REMINDER)+1, LENGTH(REMINDER)) AS ITEM,
'' AS REMINDER FROM R1 WHERE REMINDER <> '' AND LOCATE(I_DELIMITER, REMINDER) = 0
)
SELECT ITEM FROM R1;
In DB2
SELECT
'11,222,33,444' AS THE_F_STRING
, SUBSTR('11,222,33,444', 1, LOCATE_IN_STRING('11,222,33,444',',',1,1)-1) AS AA
, SUBSTR('11,222,33,444', LOCATE_IN_STRING('11,222,33,444',',',1,1)+1, LOCATE_IN_STRING('11,222,33,444',',',1,2)-LOCATE_IN_STRING('11,222,33,444',',',1,1)-1) AS BB
, SUBSTR('11,222,33,444', LOCATE_IN_STRING('11,222,33,444',',',1,2)+1, LOCATE_IN_STRING('11,222,33,444',',',1,3)-LOCATE_IN_STRING('11,222,33,444',',',1,2)-1) AS CC
, SUBSTR('11,222,33,444', LOCATE_IN_STRING('11,222,33,444',',',1,3)+1, LENGTH('11,222,33,444')-LOCATE_IN_STRING('11,222,33,444',',',1,3)) AS DD
FROM SYSIBM.SYSDUMMY1;
Keep extrapolating...enjoy...
If you are sure that each substrings are 3 characters long you can try this code, provided that TABLE1 is a table where there is at least X rows (X = 10 in this example):
select rc, substr(string_to_split, (rc-1)*3+rc, 3) as result from
(select row_number() over() as rc from TABLE1 fetch first 10 rows only) TB_rowcount
cross join
(select 'CHG-FFH' as string_to_split from sysibm.sysdummy1) T2
where substr(string_to_split, (rc-1)*3+rc, 3) <> ' '
If the length of the substrings are not the same you have to apply LOCATE function to find the separator
I needed to use instr, substr, trim, and messed with locate as well.. but instr, and substr are all supported. You can find a pattern. I had to go through a varchar split with ' - ' and needed to find the end and go back from there.
select itn,
substr(Message, 1 , locate(' - ', Message)) FIRST_SSR,
SUBSTR(Message , instr( message, ' - ', octets)+1, (instr(
message, '(Ref', octets)+1)) SECOND_STR ,
Message
from
(
select p.itn itn,
substr(p.msg, instr( p.msg, ' - ' , octets)+21) Message
from itnpad p
where p.msg like '%MR - Multiple Requests%'
) A
Suraj's answer was very close to working for me, but I needed to change the length logic slightly. I also have colons in it at this point to run it outside of a stored procedure.
WITH R1 (ITEM, REMAINDER) AS
(SELECT SUBSTR(:I_INPUTLIST, 1, LOCATE(:I_DELIMITER, :I_INPUTLIST)-1) AS ITEM,
SUBSTR(:I_INPUTLIST, LOCATE(:I_DELIMITER, :I_INPUTLIST)+1, LENGTH(:I_INPUTLIST) - LOCATE(:I_DELIMITER, :I_INPUTLIST)) REMAINDER
FROM SYSIBM.SYSDUMMY1
UNION ALL
SELECT SUBSTR(REMAINDER, 1, LOCATE(:I_DELIMITER, REMAINDER)-1) AS ITEM,
SUBSTR(REMAINDER, LOCATE(:I_DELIMITER, REMAINDER)+1, LENGTH(:I_INPUTLIST) - LOCATE(:I_DELIMITER, :I_INPUTLIST)) REMAINDER
FROM R1 WHERE LOCATE(:I_DELIMITER, REMAINDER) > 0
UNION ALL
SELECT SUBSTR(REMAINDER, LOCATE(:I_DELIMITER, REMAINDER)+1, LENGTH(:I_INPUTLIST) - LOCATE(:I_DELIMITER, :I_INPUTLIST)) AS ITEM,
'' AS REMAINDER FROM R1 WHERE REMAINDER <> '' AND LOCATE(:I_DELIMITER, REMAINDER) = 0
)
SELECT ITEM FROM R1;
DB2 11.5 LUW has a set of JSON functions that can do this.
select *
from table(
systools.json_table(systools.json2bson('{"data":' || ([1,2,3]) || }'), 'data','s:10'))
TYPE VALUE
16 1
16 2
16 3
3 record(s) selected.
you have to wrap the string in a valid json object ( which is why i concat with curly braces and a 'data' key) but then it will recursively unpack the array into rows.
CREATE TYPE CUSTOMSTRINGARRAY AS VARCHAR(1000) ARRAY[VARCHAR(1000)];
create or replace function SPLIT_STRING(inputString varchar(1000),splitor varchar(10), pos int)
returns VARCHAR(1000)
ARRAYDEMO: BEGIN
DECLARE arraySymbols CUSTOMSTRINGARRAY;
DECLARE out_str,item,str VARCHAR(1000);
DECLARE i,occ INT;
SET i = 1;
set item = '';
set str = inputString;
set occ = LENGTH(inputString) - LENGTH(REPLACE(inputString,splitor,''));
WHILE i <= occ DO
set item = substr(str,1,LOCATE_IN_STRING(str,splitor,1));
set str = replace(str,item,'');
SET arraySymbols[i] = TRIM(replace(item,splitor,''));
SET i = i + 1;
END WHILE;
set arraySymbols[i] = str;
return(arraySymbols[pos]);
end;
