How to generate sql script based on table structure

Question

I want to generate a sql script based on a table structure.
For example:
if the table is:
cid id c_value
1 1 zz
2 1 yy
3 2 zz
4 2 xx
5 3 ss
6 3 tt
The expected output is:
WITH
CHILD_tab as (
SELECT 1 cid, 1 id,'zz' c_value from dual union all
SELECT 2 cid, 1 id,'yy' c_value from dual union all
SELECT 3 cid, 2 id,'zz' c_value from dual union all
SELECT 4 cid, 2 id,'xx' c_value from dual union all
SELECT 5 cid, 3 id,'ss' c_value from dual union all
SELECT 6 cid, 3 id,'tt' c_value from dual )
Release 11.1.0.7.0

Answer 1

I'm doing a lot of XML these days (too much perhaps) so here's a solution involving XQuery.
We pass a query string and it outputs a CLOB containing the WITH clause :
SELECT DBMS_XMLGEN.Convert(
XMLQuery(
q'[concat(
"WITH t AS (
string-join(
for $i in /ROWSET/ROW
return concat( " SELECT ",
                string-join($i/*/concat("'",ora:replace(text(),"'","''"),"' ",local-name()),", "),
                " FROM dual" ),
" UNION ALL
passing dbms_xmlgen.getXMLType('SELECT * FROM scott.emp')
returning content
).getClobVal(), 1) AS WITH_CLAUSE
FROM dual;
WITH_CLAUSE
WITH t AS (
SELECT '7369' EMPNO, 'SMITH' ENAME, 'CLERK' JOB, '7902' MGR, '17/12/80' HIREDATE, '800' SAL, '20' DEPTNO FROM dual UNION ALL
SELECT '7499' EMPNO, 'ALLEN' ENAME, 'SALESMAN' JOB, '7698' MGR, '20/02/81' HIREDATE, '1600' SAL, '300' COMM, '30' DEPTNO FROM dual UNION ALL
SELECT '7521' EMPNO, 'WARD' ENAME, 'SALESMAN' JOB, '7698' MGR, '22/02/81' HIREDATE, '1250' SAL, '500' COMM, '30' DEPTNO FROM dual UNION ALL
SELECT '7566' EMPNO, 'JONES' ENAME, 'MANAGER' JOB, '7839' MGR, '02/04/81' HIREDATE, '2975' SAL, '20' DEPTNO FROM dual UNION ALL
SELECT '7654' EMPNO, 'MARTIN' ENAME, 'SALESMAN' JOB, '7698' MGR, '28/09/81' HIREDATE, '1250' SAL, '1400' COMM, '30' DEPTNO FROM dual UNION ALL
SELECT '7698' EMPNO, 'BLAKE' ENAME, 'MANAGER' JOB, '7839' MGR, '01/05/81' HIREDATE, '2850' SAL, '30' DEPTNO FROM dual UNION ALL
SELECT '7782' EMPNO, 'CLARK' ENAME, 'MANAGER' JOB, '7839' MGR, '09/06/81' HIREDATE, '2450' SAL, '10' DEPTNO FROM dual UNION ALL
SELECT '7788' EMPNO, 'SCOTT' ENAME, 'ANALYST' JOB, '7566' MGR, '19/04/87' HIREDATE, '3000' SAL, '20' DEPTNO FROM dual UNION ALL
SELECT '7839' EMPNO, 'KING' ENAME, 'PRESIDENT' JOB, '17/11/81' HIREDATE, '5000' SAL, '10' DEPTNO FROM dual UNION ALL
SELECT '7844' EMPNO, 'TURNER' ENAME, 'SALESMAN' JOB, '7698' MGR, '08/09/81' HIREDATE, '1500' SAL, '0' COMM, '30' DEPTNO FROM dual UNION ALL
SELECT '7876' EMPNO, 'ADAMS' ENAME, 'CLERK' JOB, '7788' MGR, '23/05/87' HIREDATE, '1100' SAL, '20' DEPTNO FROM dual UNION ALL
SELECT '7900' EMPNO, 'JAMES' ENAME, 'CLERK' JOB, '7698' MGR, '03/12/81' HIREDATE, '950' SAL, '30' DEPTNO FROM dual UNION ALL
SELECT '7902' EMPNO, 'FORD' ENAME, 'ANALYST' JOB, '7566' MGR, '03/12/81' HIREDATE, '3000' SAL, '20' DEPTNO FROM dual UNION ALL
SELECT '7934' EMPNO, 'MILLER' ENAME, 'CLERK' JOB, '7782' MGR, '23/01/82' HIREDATE, '1300' SAL, '10' DEPTNO FROM dual
)It may be useful for small data sets only because we quickly hit ORA-01706.