How to query all fields in Oracle?

To retrieve all fields in Oracle, you can use one of the following methods:

1. When using the SELECT * statement, all fields can be selected. For example, use the following syntax to select all fields in a table named “table_name”:
   SELECT * FROM table_name;
2. DESCRIBE statement: The DESCRIBE statement can be used to view the structure of a table, which includes detailed information about all the fields. For example, use the following syntax to view the structure of a table named “table_name”:
   DESCRIBE table_name;
3. Search data dictionary: Utilizing Oracle data dictionary views, one can access detailed information about tables and columns. For instance, by using the syntax below to query all fields of a table named “table_name”:
   SELECT column_name FROM all_tab_columns WHERE table_name = ‘table_name’;

Please be aware that using the SELECT * statement can easily select all fields, but it may also lead to performance issues, especially when there are a large number of fields or a large amount of data in the table. It is recommended to explicitly specify the desired fields instead of using the SELECT * statement.