CODEWITHSUNDEEP
sqlsql-servercase-whensnowflake-cloud-data-platform
Nick Knauer
Nick Knauer

Reputation: 4243

Based on Condition Extract Values Right of String

I have a dataset in sql that looks like this: 

    Col1    Col2
 13_DND_       5
   _DND_       6
123_ETL_      10
    ETL_      12
    DND_      15
   _ETL_      17

If Col1 contains either _DND_ or _ETL_, I want to remove everything to the left of DND_ and ETL_.

Final expected output is below: 

        Col1    Col2         Col3
  13_DND_456       5      DND_456
   _DND_de1f       6     DND_de1f
123_ETL_mene      10     ETL_mene
    ETL_test      12     ETL_test 
      DND_se      15       DND_se
   _ETL_def_      17     ETL_def_

I tried below for 1 condition but the result was NULL: 

SELECT *, CASE WHEN Col1 LIKE '%_DND_%' 
THEN RIGHT(Col1, LENGTH(Col1) - CHARINDEX('DND_', Col1)) ELSE Col1 END Col3;

Upvotes: 0

Views: 73

Answers (4)

Marcin Zukowski
Marcin Zukowski

Reputation: 4729

The shortest I can think of is simply REGEXP_REPLACE:

select col1, regexp_replace(col1, '.*_(ETL|DND)_', '\\1_') from x;
--------------+-----------------------------------------------+
     COL1     | REGEXP_REPLACE(COL1, '.*_(ETL|DND)_', '\\1_') |
--------------+-----------------------------------------------+
 13_DND_456   | DND_456                                       |
 345DND_7658  | 345DND_7658                                   |
 123_ETL_mene | ETL_mene                                      |
 _ETL_def_    | ETL_def_                                      |
 123ETL_mene  | 123ETL_mene                                   |
--------------+-----------------------------------------------+
--------------+-----------------------------------------+

Building on Gordon's asnwer:

select col1, (case when col1 like '%^_DND%' escape '^'
             then substr(col1, charindex('_DND', col1) + 1)
             when col1 like '%^_END%' escape '^'
             then substr(col1, charindex('_END', col1) + 1)
             else col1
        end) as col3 from x;
--------------+--------------+
     COL1     |     COL3     |
--------------+--------------+
 13_DND_456   | DND_456      |
 345DND_7658  | 345DND_7658  |
 123_ETL_mene | 123_ETL_mene |
 _ETL_def_    | _ETL_def_    |
 123ETL_mene  | 123ETL_mene  |
--------------+--------------+

Upvotes: 0

Nick Knauer
Nick Knauer

Reputation: 4243

This works for my needs: 

SELECT *, CASE WHEN Col1 LIKE '%_DND_%' OR Col1 LIKE '%_ETL_%'
THEN RIGHT(Col1, length(Col1) - charindex('-', Col1)) ELSE Col1 END Col3 FROM DF;

Upvotes: 0

Tab Alleman
Tab Alleman

Reputation: 31785

You forgot to use wildcards with LIKE.

Instead of this:

SELECT *, CASE WHEN Col1 LIKE '_DND_'

You want this:

SELECT *, CASE WHEN Col1 LIKE '%_DND_%'

Upvotes: 1

Gordon Linoff
Gordon Linoff

Reputation: 1269763

I would be inclined to use STUFF():

select (case when col1 like '%[_]DND%'
             then stuff(col1, 1, charindex('_DND', col1) - 1, '')
             when col1 like '%[_]END%'
             then stuff(col1, 1, charindex('_END', col1) - 1, '')
             else col1
        end) as col3

Your code doesn't work because the LIKE fails unless "DND" starts at the second position. So, it is returning NULL.

Because _ is a wildcard in LIKE, the LIKE pattern escapes it.

Upvotes: 1

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