Bad mojo. EOF found reading column header.

[ml01]

I use the library on some sensors with inserts, call procedures (even with return values) without any problems.
But I can't get a "simple" select to work. :(

Hard-/Software:
ESP8266 (wemos d1 mini) with some sensors and a relay card.
Arduino IDE 2.3.4
MySQL Connector Arduino 1.2.0
MySQL 5.1.73 - Source distribution

void setup() {
...
  // connecting to MySQL
  MySQL_Connection conn((Client *)&client);

  Serial.println("Connecting to MySQL...");
  if (conn.connect(server_addr, 3306, user, password, db)) {
    delay(1000);
  } else {
    Serial.println("Connection failed.");
    delay(2000);
    ESP.restart();
  }
  
  // Create an instance of the cursor passing in the connection
  char query1[200];
  char query2[] = "CALL DataCalc();";
  char query3[] = "SELECT int_heizkreis, str_mac FROM Wohnung_Messdaten.pipe_sensor_config";

  Serial.println("query 1");
  MySQL_Cursor *cur_mem = new MySQL_Cursor(&conn);
  sprintf(query1, "UPDATE sensor_config SET ts_letzte_meldung = NOW(), str_typ = '%s' WHERE str_mac = '%s'", IP, str_mac);
  Serial.println(query1);
  cur_mem->execute(query1);
  delete cur_mem;

  Serial.println("query 2");
  MySQL_Cursor *cur_mem2 = new MySQL_Cursor(&conn);
  row_values *row2 = NULL;
  cur_mem2->execute(query2);
  column_names *columns2 = cur_mem2->get_columns();
  row2 = cur_mem2->get_next_row();
  Relay = atol(row2->values[0]);
  Serial.println(Relay,BIN);
  IOexpanderWrite(DEVICE_1, Relay);
  delete cur_mem2;

  Serial.println("query 3");
  MySQL_Cursor *cur_mem3 = new MySQL_Cursor(&conn);
  row_values *row3 = NULL;
  cur_mem3->execute(query3);
  Serial.println("Columns start");
  column_names *columns3 = cur_mem3->get_columns();
  Serial.println("Columns done");
  do {
    row3 = cur_mem3->get_next_row();
    if (row3 != NULL) {
      int heizkreis = atoi(row3->values[0]);
      byte mac_address[8];
      char* mac_str = row3->values[1];    
...
     }
  } while (row3 != NULL);
  delete cur_mem3;
  
  conn.close();
}

and the serial output (query 3 is the problematic one)

..[WIFI] STATION Mode, SSID: WiFi1, IP address: 10.10.10.123

Connected to network
MAC-Adresse: 	98:f4:ab:db:28:3a
IP-Adresse: 	10.10.10.123
serverSetupRelay: 11
Server started
Connecting to MySQL...
...trying...
Connected to server version 5.1.73
query 1
UPDATE sensor_config SET ts_letzte_meldung = NOW(), str_typ = '10.10.10.123' WHERE str_mac = '98:f4:ab:db:28:3a'
query 2
1000000
query 3
Columns start
Bad mojo. EOF found reading column header.
Columns done
ERROR: You must read the columns first!
Disconnected.

Is there any option to skip the columns or fix the error?

[ChuckBell]

Hi, Sorry for the delay. Midterms and term papers, am I right? I believe you will need to read all the columns and rows from every query, even those that don’t return any rows. In this case, add the column and row read loop to query1 and query2. I attempted to reproduce the error, but was unable to do so. I am not sure if the issue is in your DataCalc() function. Maybe share that with me? Dr. Bell

…

On Sep 22, 2025, at 14:41, ml01 ***@***.***> wrote: ml01 created an issue (ChuckBell/MySQL_Connector_Arduino#242) <#242> I use the library on some sensors with inserts, call procedures (even with return values) without any problems. But I can't get a "simple" select to work. :( Hard-/Software: ESP8266 (wemos d1 mini) with some sensors and a relay card. Arduino IDE 2.3.4 MySQL Connector Arduino 1.2.0 MySQL 5.1.73 - Source distribution void setup() { ... // connecting to MySQL MySQL_Connection conn((Client *)&client); Serial.println("Connecting to MySQL..."); if (conn.connect(server_addr, 3306, user, password, db)) { delay(1000); } else { Serial.println("Connection failed."); delay(2000); ESP.restart(); } // Create an instance of the cursor passing in the connection char query1[200]; char query2[] = "CALL DataCalc();"; char query3[] = "SELECT int_heizkreis, str_mac FROM Wohnung_Messdaten.pipe_sensor_config"; Serial.println("query 1"); MySQL_Cursor *cur_mem = new MySQL_Cursor(&conn); sprintf(query1, "UPDATE sensor_config SET ts_letzte_meldung = NOW(), str_typ = '%s' WHERE str_mac = '%s'", IP, str_mac); Serial.println(query1); cur_mem->execute(query1); delete cur_mem; Serial.println("query 2"); MySQL_Cursor *cur_mem2 = new MySQL_Cursor(&conn); row_values *row2 = NULL; cur_mem2->execute(query2); column_names *columns2 = cur_mem2->get_columns(); row2 = cur_mem2->get_next_row(); Relay = atol(row2->values[0]); Serial.println(Relay,BIN); IOexpanderWrite(DEVICE_1, Relay); delete cur_mem2; Serial.println("query 3"); MySQL_Cursor *cur_mem3 = new MySQL_Cursor(&conn); row_values *row3 = NULL; cur_mem3->execute(query3); Serial.println("Columns start"); column_names *columns3 = cur_mem3->get_columns(); Serial.println("Columns done"); do { row3 = cur_mem3->get_next_row(); if (row3 != NULL) { int heizkreis = atoi(row3->values[0]); byte mac_address[8]; char* mac_str = row3->values[1]; ... } } while (row3 != NULL); delete cur_mem3; conn.close(); } and the serial output (query 3 is the problematic one) ..[WIFI] STATION Mode, SSID: WiFi1, IP address: 10.10.10.123 Connected to network MAC-Adresse: 98:f4:ab:db:28:3a IP-Adresse: 10.10.10.123 serverSetupRelay: 11 Server started Connecting to MySQL... ...trying... Connected to server version 5.1.73 query 1 UPDATE sensor_config SET ts_letzte_meldung = NOW(), str_typ = '10.10.10.123' WHERE str_mac = '98:f4:ab:db:28:3a' query 2 1000000 query 3 Columns start Bad mojo. EOF found reading column header. Columns done ERROR: You must read the columns first! Disconnected. Is there any option to skip the columns or fix the error? — Reply to this email directly, view it on GitHub <#242>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AB6SHYEMVL3XGNOLWXOIUTT3UA7EFAVCNFSM6AAAAACHGFTBT6VHI2DSMVQWIX3LMV43ASLTON2WKOZTGQ2DEMRTHE2TENY>. You are receiving this because you are subscribed to this thread.

[qwesza]

I am meet this problem. second query is EOF wrong