How to get row count using ResultSet in Java?

Question

If you have access to the prepared statement that results in this resultset, you can use

connection.prepareStatement(sql, 
  ResultSet.TYPE_SCROLL_INSENSITIVE, 
  ResultSet.CONCUR_READ_ONLY);

This prepares your statement in a way that you can rewind the cursor. This is also documented in the ResultSet Javadoc

In general, however, forwarding and rewinding cursors may be quite inefficient for large result sets. Another option in SQL Server would be to calculate the total number of rows directly in your SQL statement:

SELECT my_table.*, count(*) over () total_rows
FROM my_table
WHERE ...

your sql Statement creating code may be like

statement = connection.createStatement();

To solve "com.microsoft.sqlserver.jdbc.SQLServerException: The requested operation is not supported on forward only result sets" exception change above code with

statement = connection.createStatement(
    ResultSet.TYPE_SCROLL_INSENSITIVE, 
    ResultSet.CONCUR_READ_ONLY);

After above change you can use

int size = 0;
try {
    resultSet.last();
    size = resultSet.getRow();
    resultSet.beforeFirst();
}
catch(Exception ex) {
    return 0;
}
return size;

to get row count

Statement s = cd.createStatement();
ResultSet r = s.executeQuery("SELECT COUNT(*) AS rowcount FROM FieldMaster");
r.next();
int count = r.getInt("rowcount");
r.close();
System.out.println("MyTable has " + count + " row(s).");

Sometimes JDBC does not support following method gives Error like `TYPE_FORWARD_ONLY' use this solution

Sqlite does not support in JDBC.

resultSet.last();
size = resultSet.getRow();
resultSet.beforeFirst();

So at that time use this solution.

I just made a getter method.

public int getNumberRows(){
    try{
       statement = connection.creatStatement();
       resultset = statement.executeQuery("your query here");
       if(resultset.last()){
          return resultset.getRow();
       } else {
           return 0; //just cus I like to always do some kinda else statement.
       }
    } catch (Exception e){
       System.out.println("Error getting row count");
       e.printStackTrace();
    }
    return 0;
}

Do a SELECT COUNT(*) FROM ... query instead.

If you have table and storing the ID as primary and auto increment then this will work

Example code to get the total row count http://www.java2s.com/Tutorial/Java/0340__Database/GettheNumberofRowsinaDatabaseTable.htm

Below is code

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;

public class Main {
  public static void main(String[] args) throws Exception {
    Connection conn = getConnection();
    Statement st = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
        ResultSet.CONCUR_UPDATABLE);

    st.executeUpdate("create table survey (id int,name varchar(30));");
    st.executeUpdate("insert into survey (id,name ) values (1,'nameValue')");
    st.executeUpdate("insert into survey (id,name ) values (2,null)");
    st.executeUpdate("insert into survey (id,name ) values (3,'Tom')");
    st = conn.createStatement();
    ResultSet rs = st.executeQuery("SELECT * FROM survey");

    rs = st.executeQuery("SELECT COUNT(*) FROM survey");
    // get the number of rows from the result set
    rs.next();
    int rowCount = rs.getInt(1);
    System.out.println(rowCount);

    rs.close();
    st.close();
    conn.close();

  }

  private static Connection getConnection() throws Exception {
    Class.forName("org.hsqldb.jdbcDriver");
    String url = "jdbc:hsqldb:mem:data/tutorial";

    return DriverManager.getConnection(url, "sa", "");
  }
}

Your function will return the size of a ResultSet, but its cursor will be set after last record, so without rewinding it by calling beforeFirst(), first() or previous() you won't be able to read its rows, and rewinding methods won't work with forward only ResultSet (you'll get the same exception you're getting in your second code fragment).