Oracle tips

'Select Into' using dynamic sql
execute immediate 'select count(*) from dual' INTO l_cnt;
OR
sql_stmt := 'SELECT COUNT(*) FROM BACKUP_TABLE_NAME WHERE BACKUP_ID = :1';
EXECUTE IMMEDIATE sql_stmt INTO total USING state_id;

Using ampersand without variable substitution
set define off
OR
insert into companies values ('Bob &' || ' Sons');
OR
set scan off

User and Tablespace mapping
select USERNAME, DEFAULT_TABLESPACE, TEMPORARY_TABLESPACE
from dba_users
order by USERNAME