Question

I am using Postgresql and I need to run a query where I do a SELECT DISTINCT on a single string column. However I don’t want to select the column as is, I need to substring it on the first occurrence of this string ‘ (‘.

I do not know how to do this substring part..

Here is an example of the query without the substring part:

SELECT DISTINCT ON (Table.Column1) Table.Column2 
FROM Table 
ORDER BY Table.Column1

I am not sure what functions to use in postgres or possibly I need to use plpgsql to do this?

Answer 1

I managed to work this out. The function to be used is SPLIT_PART. Which takes three parameters ColumnName, Characters, And the substring occurance.

Here is an example of how I have used it.

SELECT DISTINCT ON (SPLIT_PART(Table.Column1, ' )', 1)) Table.Column2 
FROM Table 
ORDER BY SPLIT_PART(Table.Column1, ' )', 1)