sql - Any way to distinguish the cases of 0 affected row of MYSQL update? -

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suppose have table named 't'

--------------- | key | value | --------------- | 1   | abc   | | 2   | def   | ---------------

consider 2 mysql queries

  1. update t set value='abc' key=1
  2. update t set value='abc' key=3

executing both queries give 'affected rows' 0 (that is, not update row) because first query non-updating update , second non-matching update.

is there way distinguish these 2 cases?

if want number of 'matched' rows (and no longer number of 'changed' rows), can set client_found_rows described here:

http://dev.mysql.com/doc/refman/5.5/en/mysql-affected-rows.html

for update statements, affected-rows value default number of rows changed. if specify client_found_rows flag mysql_real_connect() when connecting mysqld, affected-rows value number of rows “found”; is, matched clause.


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