Update Statement Updating Too Many Rows

Question

Hiya,
I am trying to run this update statement:
UPDATE PROCEDURE_PRICE p
SET p.term_date = (SELECT t.tdate
                    FROM PROCEDURE_PRICE_TMP t
                    WHERE p.seq_proc_price = t.zzz_nullterm_seq_proc_price
                    AND p.procedure_code = t.procedure_code
                    AND p.price_schedule = t.price_schedule)
And it is updating all 600000+ records in the PROCEDURE_PRICE table.
I am only expecting it to update 60 records, because that is what I find when running this query:
select p.term_date,
     t.tdate,
     p.seq_proc_price,
     t.zzz_nullterm_seq_proc_price,
     p.procedure_code,
     t.procedure_code,
     p.price_schedule,
     t.price_schedule
from procedure_price p, procedure_price_tmp t
WHERE p.seq_proc_price = t.zzz_nullterm_seq_proc_price
AND p.procedure_code = t.procedure_code
AND p.price_schedule = t.price_schedule;
Can't seem to figure out what is wrong, and I know it is something simple.
Thanks in advance :).

Answer 1

You probably want something like
UPDATE PROCEDURE_PRICE p
   SET p.term_date = (SELECT t.tdate
                        FROM PROCEDURE_PRICE_TMP t
                       WHERE p.seq_proc_price = t.zzz_nullterm_seq_proc_price
                         AND p.procedure_code = t.procedure_code
                         AND p.price_schedule = t.price_schedule)
WHERE EXISTS (SELECT 1
                 FROM PROCEDURE_PRICE_TMP t
                WHERE p.seq_proc_price = t.zzz_nullterm_seq_proc_price
                  AND p.procedure_code = t.procedure_code
                  AND p.price_schedule = t.price_schedule)Basically, you want to slap a WHERE EXISTS clause on the UPDATE that ensures that your inner query returns a row.
Justin