In an anonymous PL/SQL block, you can't just run a SQL statement, you at a minimum need to SELECT INTO something.
select text into code from user_source fetch first 1 rows only;
-- do SOMETHING with 'code'
run with F5..
PL/SQL procedure successfully completed.
I wanted to use only one variable in a SQL-Statement.
I have now solved:
define zSuch = 'Fred';
SELECT 'SELECT * from ' || table_name || ' where ' || COLUMN_NAME || ' LIKE ''&zSuch%'';'
WHERE data_type like '%VARCHAR2' and owner = 'WODIS';
Thank you! for your help.