BEGIN
INSERT INTO authors (
 id,
 name,
 birth_date,
 gender )
 SELECT 321,
 'Hu Darwen',
 TO_DATE('19430103', 'YYYYMMDD'),
 'MALE'
 FROM dual d
 WHERE NOT EXISTS (
 SELECT 1
 FROM authors x
 WHERE x.id = 321 );
 COMMIT;
END;

SELECT 1000+1 FROM dual
SELECT NVL(LENGTH(NULL),0) FROM dual

BEGIN
UPDATE authors
SET name = UPPER(name)
WHERE id<200;
COMMIT;
END;







DELETE FROM author_publications
 WHERE id = 111;


SELECT name
 FROM authors
 WHERE birth_date < TO_DATE('19400101', 'YYYYMMDD')
 ORDER BY name;




//Alte join
SELECT a.id,
 a.name,
 p.title,
 p.written_date
 FROM authors a,
 author_publications p
 WHERE a.id = p.id
 ORDER BY a.name,
 p.written_date,
p.title;


//NEW Join
SELECT a.id,
 a.name,
 p.title,
 p.written_date
 FROM authors a join
 author_publications p
 ON a.id = p.id
 ORDER BY a.name,
 p.written_date,
p.title;