Converting a string to be used in in-clause Teradata - teradata

Question

I have a string like this ('car, bus, train')
I want to convert it to be used in an in-clause. Basically I want to convert it to
('car','bus','train'). Please how do I do this in Teradata

Answer 1

I don't know how you are getting data like that, but if you have no control over that, you can use STRTOK_SPLIT_TO_TABLE.
select t.* from table (strtok_split_to_table(1,'car, bus, train',',')
returns (outkey integer,tokennum integer,resultstring varchar(25))) as t
Run by itself, that gives you:
outkey tokennum resultstring
1 1 car
1 2 bus
1 3 train
You can use that as a derived table and join it to the table you want to filter by. Something like:
select
<your table>.*
from
<your table>
inner join (select t.* from table (strtok_split_to_table(1,'car, bus, train',',')
returns (outkey integer,tokennum integer,resultstring varchar(25))) as t) dt
on yourtable.yourcolumn = dt.resultstring

Answer 2

here is the another way of spliting the input for n number of commas and use IN clause.
SELECT regexp_substr('car,bus,train','[^,]+',1,day_of_calendar) fields
FROM sys_calendar.calendar
WHERE day_of_calendar <= (CHAR('car,bus,train') - CHAR(oreplace('car,bus,train',',','')))+1;
Output of the Query
fields
~~~~~~~~
bus
car
train
Here is the systax to use in where clause
SELECT * FROM <your table>
WHERE yourtable.requiredColumn in
(
SELECT regexp_substr('car,bus,train','[^,]+',1,day_of_calendar) fields
FROM sys_calendar.calendar
WHERE
day_of_calendar <= (CHAR('car,bus,train') - CHAR(oreplace('car,bus,train',',','')))+1
);
Basically what we are doing here is splitting the string for each comma and below function is calculating number of commas in the string
(CHAR('car,bus,train') - CHAR(oreplace('car,bus,train',',','')))+1