I highly recommend this excellent book - I've read over 50 database books and this is in my top 5.
Mr Celko writes in a highly opinionated, slightly arrogant style, I can understand how this annoys some readers.
I though find it entertaining and above all educational, because he is so good at explaining complex topics in a readable practical manner. I love his characterisation of ID Idiot developers for example which is so true. It's a shame there are so few advanced practical sql books relevant to the real world like this - most others are far too simplistic and of no value to anyone beyond beginner level.
Please somebody write some more books like this - especially focused on database programming and Postgres, for which there are no recently published books available (apart from Postgres tuning and admin).