I want a query in oracle to get the column name from the table by passing value. Means that In most of the case - We write the query like that - select * from table where column = 'value'. But in my case i don't know the column name.
Can any one suggest me. Thanks in advance...
You can try to build a dynamic query to check all the tables of your DB.
setup:
create table tab1 ( v1 varchar2(100), n1 number, v1b varchar2(100));
create table tab2 ( v2 varchar2(100), n2 number, v2b varchar2(100));
create table tab3 ( v3 varchar2(100), n3 number, v3b varchar2(100));
insert into tab1 values ('Maria', 1, 'aa');
insert into tab1 values ('xx', 2, 'bb');
insert into tab2 values ('yy', 3, 'Maria');
insert into tab2 values ('zz', 3, 'cc');
insert into tab3 values ('WW', 4, 'DD');
build the dynamic query:
select 'select table_name,
matches from (' || listagg(statement, ' UNION ALL ') within group (order by table_name) || ')
where matches > 0'
from (
select 'select ''' || table_name ||
''' as TABLE_NAME, count(1) as MATCHES from ' || table_name || ' WHERE ' ||
listagg(column_name || ' = ''Maria''', ' OR ') within group (order by column_name) as statement,
table_name
from user_tab_columns col
where data_type = 'VARCHAR2'
group by table_name
)
This will return a query, that you can run to check all the tables; in my example, this will build the query (not formatted) :
SELECT table_name, matches
FROM (SELECT 'TAB1' AS TABLE_NAME, COUNT(1) AS MATCHES
FROM TAB1
WHERE V1 = 'Maria'
OR V1B = 'Maria'
UNION ALL
SELECT 'TAB2' AS TABLE_NAME, COUNT(1) AS MATCHES
FROM TAB2
WHERE V2 = 'Maria'
OR V2B = 'Maria'
UNION ALL
SELECT 'TAB3' AS TABLE_NAME, COUNT(1) AS MATCHES
FROM TAB3
WHERE V3 = 'Maria'
OR V3B = 'Maria')
WHERE matches > 0;
Running this query will give:
TABL MATCHES
---- ----------
TAB1 1
TAB2 1
Please notice that I used USER_TAB_COLUMNS, thus searching only in the tables of the login schema; if you want to search in different schemas, you can use ALL_TAB_COLUMNS or DBA_TAB_COLUMNS, depending on what you need and on the privileges of you user; see here for something more.
Also, consider that USER_TAB_COLUMNS will get the colums of tables and views; if you want to limit your search to tables, you can join USER_TAB_COLUMNS(ALL_TAB_COLUMNS, DBA_TAB_COLUMNS) to USER_TABLES (ALL_TABLES, DBA_TABLES) by TABLE_NAME, or TABLE_NAME and OWNER If you decide to use ALL or DBA tables:
SQL> create view vTab1 as select * from tab1;
View created.
SQL> select count(1)
2 from user_tab_columns
3 where table_name = 'VTAB1';
COUNT(1)
----------
3
SQL> select count(1)
2 from user_tab_columns
3 inner join user_tables using(table_name)
4 where table_name = 'VTAB1';
COUNT(1)
----------
0
SQL>
select table_name from user_Tables where table_name = 'bogus';
