I’m trying to execute a query on eclipse at my Java program, but it always exit with a exception and don’t execute the query, I read a lot of posts here but no one of them could help me with this.
x
public static ResultSet queryAccAmount;
public static String query = " SELECT COUNT(*) s FROM (SELECT L.ACCNUMBER AS AN, L.PROD AS PRD "
+ " FROM LTRANS(nolock) L, AN(nolock) ANM "
+ " WHERE DATA BETWEEN 20210101 AND 20210228 "
+ " AND L.PRD IN (1, 2, 3) "
+ " AND L.ACCNUMBER = ANM.ACCNUMBER "
+ " AND L.ISS = ANM.ISS "
+ " AND L.PROD = ANM.PROD "
+ " AND L.MESSAGECODE <> 'MESSAGE' "
+ " GROUP BY L.PROD, L.ACCNUMBER) S; ";
public static void main(String[] args) throws InterruptedException {
Connection c = connect();
int accAmount = 0;
try {
queryAccAmount = c.createStatement().executeQuery(query);
accAmount = Integer.parseInt(queryAccAmount.getString(1));
LOG.info("Mounth total: " + accAmount);
} catch (Exception ex) {
System.out.println(ex);
} finally {
TimeUnit.SECONDS.sleep(10);
disconnect();
}
}
The error when execute the program:
But at the base have data:
I don’t know what is wrong with this, who could help me I’m already appreciate!
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Answer
You need to call executeQuery once and then read the results in loop for example Updating my comment with working example:-
import java.sql.*;
public class JDBCConnector {
// JDBC driver name and database URL
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost/EMP";
// Database credentials
static final String USER = "root";
static final String PASS = "mysql";
public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
try{
//STEP 2: Register JDBC driver
Class.forName("com.mysql.jdbc.Driver");
//STEP 3: Open a connection
System.out.println("Connecting to database...");
conn = DriverManager.getConnection(DB_URL,USER,PASS);
//STEP 4: Execute a query
System.out.println("Creating statement...");
stmt = conn.createStatement();
String sql;
sql = "SELECT id, first, last, age FROM Employees";
ResultSet rs = stmt.executeQuery(sql);
//STEP 5: Extract data from result set
while(rs.next()){
//Retrieve by column name
int id = rs.getInt("id");
int age = rs.getInt("age");
String first = rs.getString("first");
String last = rs.getString("last");
//Display values
System.out.print("ID: " + id);
System.out.print(", Age: " + age);
System.out.print(", First: " + first);
System.out.println(", Last: " + last);
}
//STEP 6: Clean-up environment
rs.close();
stmt.close();
conn.close();
}catch(SQLException se){
//Handle errors for JDBC
se.printStackTrace();
}catch(Exception e){
//Handle errors for Class.forName
e.printStackTrace();
}finally{
//finally block used to close resources
try{
if(stmt!=null)
stmt.close();
}catch(SQLException se2){
}// nothing we can do
try{
if(conn!=null)
conn.close();
}catch(SQLException se){
se.printStackTrace();
}//end finally try
}//end try
System.out.println("Goodbye!");
}//end main
}//end FirstExample