Description:
When a getTableName() is called on the metadata result set obtained from preparing an SQL query having count(*), it returns null which is change in behavior from JDBC driver version 5.1.40. 5.1.40 driver returns an empty string instead of null.
We found that it returns null with 5.1.44 driver as well but we couldn't find any documentation which states that it's a change is behavior.
How to repeat:
Run the following standalone code to reproduce the issue
package jdbc_sample_latest;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.Properties;
public class GetMedataForQuery {
public static void main(String[] args) {
// TODO Auto-generated method stub
//Replace <host>, <portNumber> and <DBName> with appropriate values.
String jdbcConnectionURL = "jdbc:mysql://<host>:<portNumber>/<DBName>";
Properties prop = new Properties();
//Replace <userName> and <password> with appropriate values.
String userName = "<userName>";
String password = "<password>";
prop.put("user", userName);
prop.put("password", password);
Connection con = null;
try{
con = DriverManager.getConnection(jdbcConnectionURL, prop);
System.out.println("connection is successful");
System.out.println("Driver version is : " + con.getMetaData().getDriverVersion());
ResultSetMetaData rsMeta;
//Replace <tableName> with appropriate value.
String query = "select count(*) from <tableName>";
PreparedStatement pstmt = con.prepareStatement(query);
rsMeta = pstmt.getMetaData();
if (rsMeta != null) {
for (int i = 1; i <= rsMeta.getColumnCount(); i++) {
System.out.println("Table Name is : " + rsMeta.getTableName(i));
}
}
}catch(SQLException e) {
e.printStackTrace();
}
}
}
Output with 8.0.12 driver for our case
----------------------------------------------------------------------------
connection is successful
Driver version is : mysql-connector-java-8.0.12 (Revision: 24766725dc6e017025532146d94c6e6c488fb8f1)
Table Name is : null
----------------------------------------------------------------------------
Output with 5.1.40 driver for our case
----------------------------------------------------------------------------
connection is successful
Driver version is : mysql-connector-java-5.1.40 ( Revision: 402933ef52cad9aa82624e80acbea46e3a701ce6 )
Table Name is :
----------------------------------------------------------------------------
Description: When a getTableName() is called on the metadata result set obtained from preparing an SQL query having count(*), it returns null which is change in behavior from JDBC driver version 5.1.40. 5.1.40 driver returns an empty string instead of null. We found that it returns null with 5.1.44 driver as well but we couldn't find any documentation which states that it's a change is behavior. How to repeat: Run the following standalone code to reproduce the issue package jdbc_sample_latest; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSetMetaData; import java.sql.SQLException; import java.util.Properties; public class GetMedataForQuery { public static void main(String[] args) { // TODO Auto-generated method stub //Replace <host>, <portNumber> and <DBName> with appropriate values. String jdbcConnectionURL = "jdbc:mysql://<host>:<portNumber>/<DBName>"; Properties prop = new Properties(); //Replace <userName> and <password> with appropriate values. String userName = "<userName>"; String password = "<password>"; prop.put("user", userName); prop.put("password", password); Connection con = null; try{ con = DriverManager.getConnection(jdbcConnectionURL, prop); System.out.println("connection is successful"); System.out.println("Driver version is : " + con.getMetaData().getDriverVersion()); ResultSetMetaData rsMeta; //Replace <tableName> with appropriate value. String query = "select count(*) from <tableName>"; PreparedStatement pstmt = con.prepareStatement(query); rsMeta = pstmt.getMetaData(); if (rsMeta != null) { for (int i = 1; i <= rsMeta.getColumnCount(); i++) { System.out.println("Table Name is : " + rsMeta.getTableName(i)); } } }catch(SQLException e) { e.printStackTrace(); } } } Output with 8.0.12 driver for our case ---------------------------------------------------------------------------- connection is successful Driver version is : mysql-connector-java-8.0.12 (Revision: 24766725dc6e017025532146d94c6e6c488fb8f1) Table Name is : null ---------------------------------------------------------------------------- Output with 5.1.40 driver for our case ---------------------------------------------------------------------------- connection is successful Driver version is : mysql-connector-java-5.1.40 ( Revision: 402933ef52cad9aa82624e80acbea46e3a701ce6 ) Table Name is : ----------------------------------------------------------------------------