Pull values from a string - sql

Question

I have a column for which I need to pull the R- value.
What would be the best way to do this?
I feel like I'm close with this but having issues getting what I need
Basically need the R- value, can be different characters long, up until the Control lab.
See example below.
select SUBSTR( err_desc, 57, INSTR (err_desc, 'Control Lab:', 1, 1)-1)
from error_log
where sql_err_text = 'EXCEEDED VARIANCE LIMIT'
and year = '2022';
Example would be:
Plant: 649 Order: 2HC2204018 Year: 2022 Cycle: 01 Raw: R-66-59-18 Control Lab: WH Variance Warning: 50 Variance Limit: 100
Required output: R-66-59-18
Plant: 650 Order: 9GM2202004 Year: 2022 Cycle: 03 Raw: R-401059 Control Lab: GR
Required output: R-401059
Tried SQL above. Was getting more characters than expected.

Answer 1

I would use REGEXP_SUBSTR() with a capture group:
SELECT err_desc, REGEXP_SUBSTR(err_desc, 'Raw: (R(-[0-9]+)+)', 1, 1, NULL, 1) AS output
FROM error_log
WHERE sql_err_text = 'EXCEEDED VARIANCE LIMIT' AND year = '2022';

Answer 2

If you just want the value from the first key-value pair where the key ends in Raw then you can use:
SELECT id,
CASE
WHEN spos = 0 THEN NULL
WHEN epos = 0 THEN SUBSTR(value, spos + 6)
ELSE SUBSTR(value, spos + 6, epos - spos - 6)
END AS raw_value
FROM (
SELECT id,
' ' || value AS value,
INSTR(' ' || value, ' Raw: ') AS spos,
INSTR(' ' || value, ' ', INSTR(' ' || value, ' Raw: ') + 6) AS epos
FROM table_name
)
or, less to type but regular expressions are much slower to execute:
SELECT id,
REGEXP_SUBSTR(value, '(^| )Raw: (\S+)', 1, 1, NULL, 2) AS raw_value
FROM table_name;
Which, for the sample data:
CREATE TABLE table_name ( id, value ) AS
SELECT 1, 'Plant: 649 Order: 2HC2204018 Year: 2022 Cycle: 01 Raw: R-66-59-18 Control Lab: WH Variance Warning: 50 Variance Limit: 100' FROM DUAL UNION ALL
SELECT 2, 'Plant: 650 Order: 9GM2202004 Year: 2022 Cycle: 03 Raw: R-401059 Control Lab: GR' FROM DUAL UNION ALL
SELECT 3, 'Plant: 651 Not Raw: NOT-THIS Raw: XYZ-123' FROM DUAL;
Both output:
ID
RAW_VALUE
1
R-66-59-18
2
R-401059
3
NOT-THIS
Note: If you have multiple key-value pairs which end in Raw then this (and the answers by other people) will get confused as to which key you want and return the first one that matches Raw.
If you want all the key-value pairs (assuming you use : to delimit between the key-value pairs and each value ends after the next space character) then you can use:
WITH bounds (id, value, spos, delim_pos, epos) AS (
SELECT id,
value,
1,
INSTR(value, ': ', 1),
INSTR(value, ' ', INSTR(value, ': ', 1) + 2)
FROM table_name
UNION ALL
SELECT id,
value,
epos + 1,
INSTR(value, ': ', epos + 1),
INSTR(value, ' ', INSTR(value, ': ', epos + 1) + 2)
FROM bounds
WHERE epos > 0
) SEARCH DEPTH FIRST BY id SET order_id,
SELECT id,
TRIM(SUBSTR(value, spos, delim_pos - spos)) AS key,
CASE epos
WHEN 0
THEN SUBSTR(value, delim_pos + 2)
ELSE SUBSTR(value, delim_pos + 2, epos - delim_pos - 2)
END AS value
FROM bounds;
Which, for the sample data, outputs:
ID
KEY
VALUE
1
Plant
649
1
Order
2HC2204018
1
Year
2022
1
Cycle
01
1
Raw
R-66-59-18
1
Control Lab
WH
1
Variance Warning
50
1
Variance Limit
100
2
Plant
650
2
Order
9GM2202004
2
Year
2022
2
Cycle
03
2
Raw
R-401059
2
Control Lab
GR
3
Plant
651
3
Not Raw
NOT-THIS
3
Raw
XYZ-123
If you only want the Raw values after getting all the keys then you can use a filter:
WITH bounds (id, value, spos, delim_pos, epos) AS (
SELECT id,
value,
1,
INSTR(value, ': ', 1),
INSTR(value, ' ', INSTR(value, ': ', 1) + 2)
FROM table_name
UNION ALL
SELECT id,
value,
epos + 1,
INSTR(value, ': ', epos + 1),
INSTR(value, ' ', INSTR(value, ': ', epos + 1) + 2)
FROM bounds
WHERE epos > 0
) SEARCH DEPTH FIRST BY id SET order_id,
key_value_pairs (id, key, value) AS (
SELECT id,
TRIM(SUBSTR(value, spos, delim_pos - spos)),
CASE epos
WHEN 0
THEN SUBSTR(value, delim_pos + 2)
ELSE SUBSTR(value, delim_pos + 2, epos - delim_pos - 2)
END
FROM bounds
)
SELECT *
FROM key_value_pairs
WHERE key = 'Raw';
Which outputs:
ID
KEY
VALUE
1
Raw
R-66-59-18
2
Raw
R-401059
3
Raw
XYZ-123
Which will get the correct key if there are multiple ending in Raw.
fiddle

Answer 3

Option with the substr + instr combination; you have to find where Raw starts, and then subtract Control and Raw position (to find substring length). +5 (as well as -5) represents "Raw", colon and space. +1 is here to properly set substring length.
SQL> with error_log (err_desc) as
2 (select 'Plant: 649 Order: 2HC2204018 Year: 2022 Cycle: 01 Raw: R-66-59-18 Control Lab: WH Variance Warning: 50 Variance Limit: 100' from dual union all
3 select 'Plant: 650 Order: 9GM2202004 Year: 2022 Cycle: 03 Raw: R-401059 Control Lab: GR' from dual
4 )
5 select substr(err_desc, instr(err_desc, 'Raw') + 5,
6 instr(err_desc, 'Control') - instr(err_desc, 'Raw') - 5 + 1
7 ) result
8 from error_log;
RESULT
--------------------------------------------------------------------------------
R-66-59-18 C
R-401059 C
SQL>