int mysql_select_db(MYSQL *mysql, const char *db)
Causes the database specified by
become the default (current) database on the connection
mysql. In subsequent queries,
this database is the default for table references that include
no explicit database specifier.
mysql_select_db() fails unless
the connected user can be authenticated as having permission
to use the database or some object within it.
Commands were executed in an improper order.
The MySQL server has gone away.
The connection to the server was lost during the query.
An unknown error occurred.