mysql_connection.ConnectionString = "server=xxxx;" _
& "uid=xxxx;" _
& "pwd=xxxxx;" _
& "database=xxxx;" _
& "port=xxxxx;" _
& "Pooling=true;" _
& "Min Pool Size=0;" _
& "Max Pool Size=10000;" _
& "Connection Lifetime=3600;" _
& "Charset=latin1;"
 
mysql_command.Connection = mysql_connection
 
mysql_command.CommandText = "INSERT INTO memory_table (x,y,z) SELECT x,y,z FROM" & _
  "tabelle WHERE dayofyear(from_unixtime(xxx.timestamp))  = dayofyear(" & _
  "from_unixtime(UNIX_TIMESTAMP())) - 1"
 
mysql_connection.Open()
mysql_command.ExecuteNonQuery()
mysql_connection.Close()