MySQL Bugs: #2247: mysql_stmt_affected_rows returns affected rows from last command

Bug #2247	mysql_stmt_affected_rows returns affected rows from last command
Submitted:	1 Jan 2004 7:35	Modified:	20 Feb 2004 3:15
Reporter:	Georg Richter
Status:	Closed
Category:	Server	Severity:	S3 (Non-critical)
Version:	4.1.2	OS:	Any (any)
Assigned to:	Konstantin Osipov	Target Version:

Description:
I'm not sure if it's a documentation or implementation bug:

http://www.mysql.com/doc/en/mysql_stmt_affected_rows.html
Returns the total number of rows changed, deleted, or inserted by the last executed
statement.

mysql_stmt_affected_rows returns stmt->mysql->last_used_conn->affected_rows which means it
will change also when you execute a query, not only a prepared statement. If this is
expected behaviour do we need an additional api function, when you can also retrieve this
value with mysql_affected_rows ?

How to repeat:
...
stmt = mysql_prepare(mysql, "INSERT INTO foo VALUES (1),(2),(3)", 100);
mysql_execute(stmt);

/* should be 3 */
printf("Affected rows: %d\n", mysql_stmt_affected_rows(stmt));

mysql_query(mysql, "UPDATE foo SET a=7 WHERE a=1");

/* should be 3 but is 1 */
printf("Affected rows: %d\n", mysql_stmt_affected_rows(stmt));
..

Verifying, though this sounds more like a matter that needs internal discussion.

This is description of 2291 which is a copy of this bug:

Description: Implementation of mysql_stmt_affected_rows() is the following:
/*  
  Return total affected rows from the last statement
*/
  
my_ulonglong STDCALL mysql_stmt_affected_rows(MYSQL_STMT *stmt)
{ 
  return stmt->mysql->last_used_con->affected_rows;
}
  

We should return statement-local variable here, otherwise that call is nothing
but usual mysql_affected_rows

How to repeat:
-

Suggested fix:
Add statement-local variable affected_rows and copy it from
mysql->last_used_conn->affected_rows in execute() function of  libmysql.c

Fixed in 4.1.2, bk commit - 4.1 tree (konstantin:1.1694)