I have a custom query and I need to know how to extract colum names from this. I've already searched for any way to do it:
This is the code I have tried to test my regex:
DECLARE
v_SQL VARCHAR2(32767 CHAR);
v_Result VARCHAR2(32767 CHAR);
BEGIN
v_SQL := 'SELECT
ALIASBASE.CDCMPANY,
ALIASBASE.PAFCODCTR,
ALIASBASE.PAFDTSCAD,
NUMFLUSSO.NUMERO,
ALIASBASE.PAFDESC,
ALIASBASE.PAFTYPE,
ALIASBASE.PAFNATURE,
ALIASBASE.PAFRECEIV,
ALIASBASE.PAFCAUSAL,
ALIASBASE.PAFCODDNE,
ALIASBASE.PAFMATURITY
FROM ALBSIAE';
BEGIN
SELECT
REGEXP_SUBSTR (v_SQL, '(?:\s*(?=\w+\.|.*as\s+|)(\*|\w+)(?=\s*(?=,|from)))',1, NULL,'i') REGEX_RESULT
INTO
v_Result
FROM DUAL;
END;
DBMS_OUTPUT.put_line('v_Result: ' || v_Result);
END;
But ant the end the v_Result is empty.
So, I want to know if is there any other way to do this, am I wrong with the regex? Is something wrong in it? Does Oracle have other regex syntax?
You can parse the statement with DBMS_SQL.parse and get the columns with DBMS_SQL.describe_columns :
DECLARE
v_SQL VARCHAR2(32767 CHAR);
v_Result VARCHAR2(32767 CHAR) := '';
l_cursor PLS_INTEGER;
l_col_cnt PLS_INTEGER;
i PLS_INTEGER;
l_desc_tab DBMS_SQL.desc_tab;
BEGIN
v_SQL := q'[SELECT 1 as "MY_NUMBER", 'z' as "MY_CHAR" from dual]';
l_cursor := DBMS_SQL.open_cursor;
DBMS_SQL.parse(l_cursor, v_SQL, DBMS_SQL.native);
DBMS_SQL.describe_columns(l_cursor, l_col_cnt, l_desc_tab);
FOR i IN 1 .. l_col_cnt LOOP
v_Result := v_Result ||' ' || l_desc_tab(i).col_name;
END LOOP;
DBMS_OUTPUT.put_line('v_Result: ' || v_Result);
END;
/
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