Extract TEXT from a CLOB field - oracle

Question

I have a CLOB field in my Oracle Database that store TEXT data in the following format:
__99__RU_LOCKED=N;;__99__RU_SUSPENDED=Y;;__17__USER_TYPE=A;;__17__USER_TYPE_610=A;;__17__GUIFLAG=0;;__17__DEFAULT_LANG_610=E;;__17__OUTPUT_DEVICE_46=LOCL;;__17__PRINT_IMMED=G;;__17__DELETE_AFTER_PRINT=D;;__17__CATT=*BLANK;;__17__CATT_46=*;;__17__DEC_FORMAT=*BLANK;;__17__DEC_FORMAT_46=X;;__17__DATE_FORMAT=2;;__17__PARAMETERS=OM_OBJM_NO_DISPLAYX;;__17__MEAS_EASLPFL=0;;__17__USER_GROUP=S1BR22;;__17__VALID_FROM=20080222;;__17__VALID_UNTIL=99991231;;__17__ACCOUNT=37004968;;
I'm using TOAD and while I am creating the query I can read the CLOB field with the following:
--- To read the CLOB field.
select DBMS_LOB.substr(ADD_INFO_MASTER) from USER
This select return me the CLOB field HUMAN READABLE.
My question is: Is there any way to extract the one single value like ACCOUNT value from the line above?
Keep in mind that this CLOB field can variate and the __17__ACCOUNT= will not be in the same place every time. I need a way to extract to locate the ;;__17__ACCOUNT= (this will be a pattern) and extract the the value 37004968.
It is possible to achieve this while performing a query in TOAD?

Answer 1

If you want to deal with CLOB values larger than 4000 symbols length (Oracle 11g) or 32K length (Oracle 12c) then you must use DBMS_LOB package.
This package contains instr() and substr() functions which operates on LOBs.
In your case query looks like that:
with prm as (
select '__17__ACCOUNT' as fld_start from dual
)
select
dbms_lob.substr(
text,
-- length of substring
(
-- position of delimiter found after start of desired field
dbms_lob.instr(text, ';;', dbms_lob.instr(text, prm.fld_start))
-
-- position of the field description plus it's length
( dbms_lob.instr(text, prm.fld_start) + length(fld_start) + 1 )
),
-- start position of substring
dbms_lob.instr(text,prm.fld_start) + length(fld_start) + 1
)
from
text_table,
prm
Query above uses this setup:
create table text_table(text clob);
insert into text_table(text) values (
'__99__RU_LOCKED=N;;__99__RU_SUSPENDED=Y;;__17__USER_TYPE=A;;__17__USER_TYPE_610=A;;__17__GUIFLAG=0;;__17__DEFAULT_LANG_610=E;;__17__OUTPUT_DEVICE_46=LOCL;;__17__PRINT_IMMED=G;;__17__DELETE_AFTER_PRINT=D;;__17__CATT=*BLANK;;__17__CATT_46=*;;__17__DEC_FORMAT=*BLANK;;__17__DEC_FORMAT_46=X;;__17__DATE_FORMAT=2;;__17__PARAMETERS=OM_OBJM_NO_DISPLAYX;;__17__MEAS_EASLPFL=0;;__17__USER_GROUP=S1BR22;;__17__VALID_FROM=20080222;;__17__VALID_UNTIL=99991231;;__17__ACCOUNT=37004968;;'
);
For everyday use with development tools it may be useful to define a function which returns value of field with desired name and use it instead of writing complicated expressions each time.
E.g. :
create or replace function get_field_from_text(
pi_text in clob,
pi_field_name in varchar2
) return varchar2 deterministic parallel_enable
is
v_start_pos binary_integer;
v_field_start varchar2(4000);
v_field_value varchar2(32767);
begin
if( (pi_text is null) or (pi_field_name is null) ) then
return null;
end if;
v_field_start := pi_field_name || '=';
v_start_pos := dbms_lob.instr(pi_text, v_field_start);
if(v_start_pos is null) then
return null;
end if;
v_start_pos := v_start_pos + length(v_field_start);
v_field_value := dbms_lob.substr(
pi_text,
(dbms_lob.instr(pi_text, ';;', v_start_pos) - v_start_pos),
v_start_pos
);
return v_field_value;
end;
Usage:
select get_field_from_text(text,'__17__OUTPUT_DEVICE_46') from text_table

Answer 2

You could use a regular expression to extract the value:
WITH your_table AS (
SELECT '__99__RU_LOCKED=N;;__99__RU_SUSPENDED=Y;;__17__USER_TYPE=A;;__17__USER_TYPE_610=A;;__17__GUIFLAG=0;;__17__DEFAULT_LANG_610=E;;__17__OUTPUT_DEVICE_46=LOCL;;__17__PRINT_IMMED=G;;__17__DELETE_AFTER_PRINT=D;;__17__CATT=*BLANK;;__17__CATT_46=*;;__17__DEC_FORMAT=*BLANK;;__17__DEC_FORMAT_46=X;;__17__DATE_FORMAT=2;;__17__PARAMETERS=OM_OBJM_NO_DISPLAYX;;__17__MEAS_EASLPFL=0;;__17__USER_GROUP=S1BR22;;__17__VALID_FROM=20080222;;__17__VALID_UNTIL=99991231;;__17__ACCOUNT=37004968;;' clob_field FROM DUAL
)
SELECT REGEXP_SUBSTR(clob_field,'__17__ACCOUNT=.*;;')
FROM your_table
Using that you would get "__17__ACCOUNT=37004968;;". You can easily extract the value with SUBSTR.
I think that in Oracle 11g REGEXP_SUBSTR has extra parameters that would let you extract a certain group within the regular expression.

Answer 3

You can use INSTR and SUBSTR with CLOB datatype:
WITH T1 AS (
SELECT '__99__RU_LOCKED=N;;__99__RU_SUSPENDED=Y;;__17__USER_TYPE=A;;__17__USER_TYPE_610=A;;__17__GUIFLAG=0;;__17__DEFAULT_LANG_610=E;;__17__OUTPUT_DEVICE_46=LOCL;;__17__PRINT_IMMED=G;;__17__DELETE_AFTER_PRINT=D;;__17__CATT=*BLANK;;__17__CATT_46=*;;__17__DEC_FORMAT=*BLANK;;__17__DEC_FORMAT_46=X;;__17__DATE_FORMAT=2;;__17__PARAMETERS=OM_OBJM_NO_DISPLAYX;;__17__MEAS_EASLPFL=0;;__17__USER_GROUP=S1BR22;;__17__VALID_FROM=20080222;;__17__VALID_UNTIL=99991231;;__17__ACCOUNT=37004968;;' TEXT FROM DUAL
)
SELECT SUBSTR(TEXT,
INSTR(TEXT, '__17__ACCOUNT=') + LENGTH('__17__ACCOUNT') + 1, -- find the first position of the value
INSTR (TEXT, ';;', INSTR(TEXT, '__17__ACCOUNT=')) - (INSTR(TEXT, '__17__ACCOUNT=') + LENGTH('__17__ACCOUNT') + 1) -- length to read. Difference between the end position (the first ;; after your placeholder) and the value start position (the same value as above)
)
FROM T1;
However I like the REGEXP solution proposed by pablomatico more.