Without knowing the name of a table and columns I want to query the database retrieve the table and columns names and then query the given tables.
I have an Oracle database schema that is like the following:
Item Table ================= Item_id, Item_type, 1 box 2 book 3 box Book Table =============== Item_id, title, author 2 'C# Programer', 'Joe' Box Table ===================== Item_id, Size 1, 'Large' 3, 'X Large' Column_mapping Table ======================= Item_type, column_name, display_order box, Size, 1 book, title, 1 book, author 2 Table_mapping Table ======================== Item_type, Table_name box, Box book, Book
I would like a SQL statement that would give something like the following results.
Item_id, Item_type column1 column2 ==================================== 1, box, 'Large', <null> 2, book, 'C# Programer', 'Joe' 3, box, 'X Large', <null>
When I tried the simpilfied querry
Select * from (select Table_name from Table_mapping where Item_type = 'box') where Item_id = 1;
I get an error that Item_id is invalid identifier
and if I try
Select * from (select Table_name from Table_mapping where Item_type = 'box');
I just get
Table_name =========== Box
I am not sure how to proceed.