ORACLE SQL CSV列比较

Question

I have a table with CSV values as column. I want use that column in where clause to compare subset of CSV is present or not. For example Table has values like

1| 'A,B,C,D,E'

Query:

select id from tab where csv_column contains 'A,C' ;

This query should return 1.

How to achieve this in SQL?

Answer 1

You can handle this using LIKE , making sure to search for the three types of pattern for each letter/substring which you intend to match:

SELECT id
FROM yourTable
WHERE (csv_column LIKE 'A,%' OR csv_column LIKE '%,A,%' OR csv_column LIKE '%,A')
      AND
      (csv_column LIKE 'C,%' OR csv_column LIKE '%,C,%' OR csv_column LIKE '%,C')

Note that match for the substring A means that either A, , ,A, or ,A appears in the CSV column.

We could also write a structurally similar query using INSTR() in place of LIKE , which might even give a peformance boost over using wildcards.

Answer 2

there's probably something funky you can do with regular expressions but in simple terms... if A and C will always be in that order

csv_column LIKE '%A%C%'

otherwise

(csv_column LIKE '%A%' AND csv_column LIKE '%C%' )

Answer 3

If you don't want to edit your search string, this could be a way:

select *
from yourTable
where csv like '%' || replace('A,C', ',', '%') || '%' 

For example:

with yourTable(id, csv) as (
  select 1, 'A,B,C,D,E' from dual union all
  select 2, 'A,C,D,E'   from dual union all
  select 3, 'B,C,D,E'   from dual 
)
select *
from yourTable
where csv like '%' || replace('A,C', ',', '%') || '%' 

gives:

        ID CSV
---------- ---------
         1 A,B,C,D,E
         2 A,C,D,E

Consider that this will only work if the characters in the search string have the same order of the CSV column; for example:

with yourTable(id, csv) as (
  select 1, 'C,A,B' from dual 
)
select *
from yourTable
here csv like '%' || replace('A,C', ',', '%') || '%' 

will give no results

Answer 4

为什么不将值存储为单独的列，然后使用简单的谓词过滤？