I used mysql-connector-java-5.1.38 to operate mysql-community-5.7.10.0 on Windows 10 64-bit.
I try to bind value in limit for pagination
"SELECT * FROM employee LIMIT ?, ?"
However the result shows:
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?, ?' at line 1
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
at com.mysql.jdbc.Util.getInstance(Util.java:387)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:939)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3878)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3814)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2478)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2625)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2547)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2505)
at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1370)
at SqlTest.main(SqlTest.java:65)
However, I tried sql in navicat directly but could get the correct answer:
INSERT INTO employee VALUES (1, 'Zara');
INSERT INTO employee VALUES (2, 'Zara');
INSERT INTO employee VALUES (3, 'Zara');
INSERT INTO employee VALUES (4, 'Zara');
SET #skip=1; SET #numrows=5;
PREPARE STMT FROM 'SELECT * FROM employee LIMIT ?, ?';
EXECUTE STMT USING #skip, #numrows;
Here is my entire code:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class SqlTest {
// JDBC driver name and database URL
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost:3306/employee?useServerPrepStmts=false";
// Database credentials
static final String USER = "root";
static final String PASS = "whaty123";
static final int PAGESIZE = 10;
public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
PreparedStatement pStmt = null;
// STEP 2: Register JDBC driver
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
// STEP 3: Open a connection
System.out.println("Connecting to database...");
try {
conn = DriverManager.getConnection(DB_URL, USER, PASS);
} catch (SQLException e) {
e.printStackTrace();
}
String insertPreparedSql = "INSERT INTO employee " + "VALUES (?, 'Zara')";
try {
pStmt = conn.prepareStatement(insertPreparedSql);
} catch (SQLException e) {
e.printStackTrace();
}
for (int i = 0; i < 100; i++) {
try {
pStmt.setInt(1, i);
pStmt.execute();
} catch (SQLException e) {
e.printStackTrace();
}
}
String selectLimitSql = "SELECT * FROM employee LIMIT ?, ?";
// select with limit
try {
pStmt = conn.prepareStatement(selectLimitSql);
pStmt.setFetchSize(PAGESIZE);
pStmt.setMaxRows(PAGESIZE);
pStmt.setFetchDirection(ResultSet.FETCH_FORWARD);
int pageNo = 0;
pStmt.setInt(1, pageNo * PAGESIZE);
pStmt.setInt(2, PAGESIZE);
ResultSet rs = pStmt.executeQuery(selectLimitSql);
while (!rs.wasNull()) {
while(rs.next()) {
System.out.println("id: " + String.valueOf(rs.getInt(1)) + " name: " + rs.getString(2));
}
pageNo = pageNo + 1;
pStmt.setInt(1, pageNo * PAGESIZE);
pStmt.setInt(2, PAGESIZE);
pStmt.executeQuery(selectLimitSql);
}
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
Your problem is not about the syntax or MySQL support for LIMIT since it's supported. The problem is about the way you are executing the PreparedStatement.
When using PreparedStatement you may not use the executeQuery(String sql), because you've prepared the SQL string formerly for the execution, and no need to pass it again in the executeQuery() method. So do this
ResultSet rs = pStmt.executeQuery();
instead of
ResultSet rs = pStmt.executeQuery(selectLimitSql);
With passing again the selectLimitSql (like above line), you are ignoring the following lines:
pStmt.setInt(1, pageNo * PAGESIZE);
pStmt.setInt(2, PAGESIZE);
and it is like executing your primitive pure sql which contains '?, ?' place holders and you get that exception.
You do not need to pass the query string. Do this
ResultSet rs = pStmt.executeQuery();
instead of
ResultSet rs = pStmt.executeQuery(selectLimitSql);
Also, remove the following lines as pagination is taken care of limit in query itself.
pStmt.setFetchSize(PAGESIZE);
pStmt.setMaxRows(PAGESIZE);
pStmt.setFetchDirection(ResultSet.FETCH_FORWARD);
Following code works:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class SqlTest {
// JDBC driver name and database URL
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost:3306/company?useServerPrepStmts=false";
// Database credentials
static final String USER = "root";
static final String PASS = "rohan";
static final int PAGESIZE = 10;
public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
PreparedStatement pStmt = null;
// STEP 2: Register JDBC driver
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
// STEP 3: Open a connection
System.out.println("Connecting to database...");
try {
conn = DriverManager.getConnection(DB_URL, USER, PASS);
} catch (SQLException e) {
e.printStackTrace();
}
String insertPreparedSql = "INSERT INTO employee " + "VALUES (?, 'Zara', 'Zara','Zara')";
try {
pStmt = conn.prepareStatement(insertPreparedSql);
} catch (SQLException e) {
e.printStackTrace();
}
for (int i = 0; i < 100; i++) {
try {
pStmt.setInt(1, i*10);
pStmt.execute();
} catch (SQLException e) {
e.printStackTrace();
}
}
String selectLimitSql = "SELECT * FROM employee limit ?, ?";
// select with limit
try {
pStmt = conn.prepareStatement(selectLimitSql);
int pageNo = 0;
pStmt.setInt(1, pageNo * PAGESIZE);
pStmt.setInt(2, PAGESIZE);
ResultSet rs = pStmt.executeQuery();
while (!rs.wasNull()) {
while(rs.next()) {
System.out.println("id: " + String.valueOf(rs.getInt(1)) + " name: " + rs.getString(2));
}
pageNo = pageNo + 1;
pStmt.setInt(1, pageNo * PAGESIZE);
pStmt.setInt(2, PAGESIZE);
rs = pStmt.executeQuery();
}
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
Related
I have a login servlet where I have a login query in my post method from the query I am getting username, password, company name and ID
I am storing all this values in a variable like
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String companyDB,nameDB,idDB;
try {
con = DBConnection.createConnection();
statement = con.createStatement();
String sql = " SELECT MT_USERS.MT_USERS_VCLOGINCODE AS USERID, MT_USERS.MT_USERS_VCUSERPASSWORD AS PASSWORDID, MT_USERS.MT_USERS_VCUSERNAME AS NAME, (SELECT MT_DISTRIBUTR_VCDISTRIBUTRNAME FROM MT_DISTRIBUTR WHERE MT_DISTRIBUTR_VCDISTRIBUTRCODE = MT_USERS.MT_DISTRIBUTR_VCDISTRIBUTRCODE) AS COMPANYNAME ,(SELECT mt_distributr_vcdistributrcode FROM mt_distributr WHERE MT_DISTRIBUTR_VCDISTRIBUTRCODE = MT_USERS.MT_DISTRIBUTR_VCDISTRIBUTRCODE) AS ID FROM MT_USERS WHERE MT_USERS_VCLOGINCODE='admin' AND MT_USERS_VCUSERPASSWORD ='admin'";
resultSet = statement.executeQuery(sql);
if (resultSet.next()) {
companyDB = resultSet.getString("COMPANYNAME");
nameDB = resultSet.getString("name");
idDB = resultset.getString("ID");
}
} catch (SQLException e) {
e.printStackTrace();
}
}
Now I have an another class where I am writing a query and in that query I want to use idDB like
My new class is
public class Outlet {
Connection con = null;
Statement statement = null;
ResultSet resultSet = null;
public List<String> getoutlet() throws ClassNotFoundException, SQLException {
List<String> list = new ArrayList<String>();
con = DBConnection.createConnection();
statement = con.createStatement();
try {
ResultSet resultSet = statement.executeQuery("select * from ecustomer where CUSTOMERIDENTIFIER in(select CUSTOMERIDENTIFIER from mt_distributrol where mt_distributr_vcdistributrcode = 'AAAA'");
while (resultSet.next()) {
list.add(resultSet.getString("CUSTOMERDESCRIPTOR"));
}
} catch (SQLException e) {
e.printStackTrace();
}
return list;
}
}
Where mt_distributr_vcdistributrcode = 'AAAA'" at the place of 'AAAA' I have to pass a variable which has the value of idDB
You may use a prepared statement here:
String sql = "SELECT CUSTOMERDESCRIPTOR FROM ecustomer WHERE CUSTOMERIDENTIFIER IN (";
sql += "SELECT CUSTOMERIDENTIFIER FROM mt_distributrol ";
sql += "WHERE mt_distributr_vcdistributrcode = ?)");
PreparedStatement ps = con.prepareStatement(sql);
ps.setString(1, "AAAA");
ResultSet rs = ps.executeQuery();
while (rs.next()) {
list.add(resultSet.getString("CUSTOMERDESCRIPTOR"));
}
I actually find that MkYong does a good job of explaining prepared statements in Java, see here, but any good documentation is a good place to start looking. And see Oracle Tutorial.
I have a bit of a problem with inserting some data in the database. The data is being read by an CSV parser and changed to data besides that, I continue to get this error message:
Connected to the PostgreSQL server successfully.
Naam van de garage: P_Erasmusbrug, Longditude: 4.482313155, Latitude: 51.91024645
org.postgresql.util.PSQLException: The column index is out of range: 1, number of columns: 0.
at org.postgresql.core.v3.SimpleParameterList.bind(SimpleParameterList.java:65)
at org.postgresql.core.v3.SimpleParameterList.setStringParameter(SimpleParameterList.java:128)
at org.postgresql.jdbc.PgPreparedStatement.bindString(PgPreparedStatement.java:1023)
at org.postgresql.jdbc.PgPreparedStatement.setString(PgPreparedStatement.java:374)
at org.postgresql.jdbc.PgPreparedStatement.setString(PgPreparedStatement.java:358)
at Database.ConnectDatabase.parser(ConnectDatabase.java:80)
at Events.CSVReader.main(CSVReader.java:40)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)
Thank you for your service.
Naam van de garage: P_St.Jacobsplaats, Longditude: 4.482054381, Latitude: 51.92410235
Thank you for your service.
Naam van de garage: P_Schouwburgplein, Longditude: 4.473618335, Latitude: 51.92102728
org.postgresql.util.PSQLException: The column index is out of range: 1, number of columns: 0.
Which continues for all the other lines of data. Is there maybe a way to fix this as I don't really understand what the error message includes..
The a, b2, and c2 are variables for the ''name'' , ''londitude'' and ''latitude''.
package Database;
import java.io.*;
import java.sql.*;
import java.util.HashMap;
import java.sql.SQLException;
public class ConnectDatabase {
private final String url = "jdbc:postgresql://localhost/Project3";
private final String user = "postgres";
private final String password = "kaas123";
private Connection conn;
public Connection connect() {
Connection conn = null;
try {
conn = DriverManager.getConnection(url, user, password);
System.out.println("Connected to the PostgreSQL server successfully.");
} catch (SQLException exception) {
System.out.println(exception.getMessage());
}
this.conn = conn;
return conn;
}
public HashMap getGarages() {
HashMap<String, Double> newHashMap = new HashMap<String, Double>();
try {
Statement stmt = conn.createStatement();
ResultSet rs;
rs = stmt.executeQuery("SELECT deelgemeente, COUNT(garagenaam) FROM garages GROUP BY deelgemeente");
while (rs.next()) {
String deelGemeenteNaam = rs.getString("deelgemeente");
double garageNaamCount = rs.getDouble("COUNT");
newHashMap.put(deelGemeenteNaam, garageNaamCount);
}
} catch (Exception e) {
System.err.println("Got an exception!");
System.err.println(e.getMessage());
}
return newHashMap;
}
public HashMap getTheftYear(int year) {
HashMap<String, Double> newHashMap = new HashMap<String, Double>();
try {
Statement stmt = conn.createStatement();
ResultSet rs;
rs = stmt.executeQuery("SELECT deelgemeente, percentagediefstal FROM autodiefstal WHERE jaar = " + year);
while (rs.next()) {
String deelGemeenteNaam = rs.getString("deelgemeente");
double deelPercentage = rs.getDouble("percentagediefstal");
newHashMap.put(deelGemeenteNaam, deelPercentage);
}
} catch (Exception e) {
System.err.println("Got an exception!");
System.err.println(e.getMessage());
}
return newHashMap;
}
public int parser(String a, float b2, float c2) {
int updated = 0;
Connection conn = null;
PreparedStatement stmt = null;
try {
conn = DriverManager.getConnection(url, user, password);
String insertSQL = "INSERT INTO testparser(garagenaam, xpos, ypos) VALUES(" + a + "," + b2 + "," + c2 + ")";
stmt = conn.prepareStatement(insertSQL);
stmt.setString(1, a);
stmt.setFloat(2, b2);
stmt.setFloat(3, c2);
System.out.println("Inserted data into the database...");
updated = stmt.executeUpdate();
} catch (SQLException se) {
se.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (stmt != null)
conn.close();
} catch (SQLException se) {
}
try {
if (conn != null)
conn.close();
} catch (SQLException se) {
se.printStackTrace();
}
}
System.out.println("Thank you for your service.");
this.conn = conn;
return updated;
}
}
You aren't correctly using the ? placeholders system, replace :
String insertSQL = "INSERT INTO testparser(garagenaam, xpos, ypos) VALUES(" + a + "," + b2 + "," + c2 + ")";
with
String insertSQL = "INSERT INTO testparser(garagenaam, xpos, ypos) VALUES(?,?,?)";
I am working with batch prepared statement.
import java.sql.*;
import java.util.Arrays;
public class QryBtch {
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost/test";
static final String USER = "root";
static final String PASS = "roottoor";
public static void main(String[] args) {
Connection conn = null;
int[] results = null;
try{
Class.forName("com.mysql.jdbc.Driver");
System.out.println("Connecting to database...");
conn = DriverManager.getConnection(DB_URL,USER,PASS);
PreparedStatement ps = null;
String query = "insert into mytable (Emp_ID, Emp_Name) values (?,?)";
ps = conn.prepareStatement(query);
String name1 = "Name1";
String name2="Big Big Name Name 1"; //longer than column length
String name3="Name2";
ps.setInt(1, 1);
ps.setString(2, name1);
ps.addBatch();
ps.setInt(1, 2);
ps.setString(2, name2);
ps.addBatch();
ps.setInt(1, 3);
ps.setString(2, name3);
ps.addBatch();
results = ps.executeBatch();
System.out.println(Arrays.toString(results));
conn.close();
}catch(SQLException se){
System.out.println(Arrays.toString(results));
se.printStackTrace();
}catch(Exception e){
e.printStackTrace();
}finally{
try{
if(conn!=null)
conn.close();
}catch(SQLException se){
se.printStackTrace();
}
}
System.out.println("Goodbye!");
}
}
I am trying to insert into a table having name defined as 8 character. So as expected my second statement got failed. Is it possible to track the statement that has been failed or the bind values for error handling.
I have created a table flight_data(with 9 columns) in the DB FLIGHT_INFO. This table has all columns as VARCHAR(3or4or5) .Although I am able to add rows in the table(through another java class) but I want to write a java class which is able to read each rows of that table. (Note : the main class DBaseReader.readDB();) Here's my effort
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class DBaseReader {
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost/FLIGHT_INFO";
static final String USER = "root";
static final String PASS = "123456";
private static Connection conn = null;
private static Statement stmt = null;
public static void readDB() {
String sql = "SELCET * FROM flight_data;"; //removing semi-colon doesn't solve problem
ResultSet rs = null;
String flightNo = null;
String dep = null;
String arr = null;
String date = null;
String flightTime = null;
String flightDuration = null;
String fare = null;
String seat_aval = null;
String flight_class = 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();
rs = stmt.executeQuery(sql);//line 47 where error occurs
// STEP 5: Extract data from result set
while (rs.next()) {
flightNo = rs.getString("flight_no");
dep = rs.getString("dep");
arr = rs.getString("arr");
date = rs.getString("valid_till");
flightTime = rs.getString("flight_time");
flightDuration = rs.getString("flight_dur");
fare = rs.getString("fare");
seat_aval = rs.getString("seat_aval");
flight_class = rs.getString("flight_class");
}
// Display values
System.out.print("FLIGHT_NO: " + flightNo);
System.out.print("DEP: " + dep);
System.out.print("ARR: " + arr);
System.out.println("VALID_TILL: " + date);
System.out.print("FLIGHT_TIME: " + flightTime);
System.out.print("FLIGHT_DUR: " + flightDuration);
System.out.print("FARE" + fare);
System.out.println("SEAT_AVAL: " + seat_aval);
System.out.println("FLIGHT_CLASS: " + flight_class);
stmt.close();
conn.close();
} catch (SQLException se) {
// Handle errors for JDBC
se.printStackTrace();
} catch (Exception e) {
// Handle errors for Class.forName
e.printStackTrace();
}
try {
if (conn != null)
conn.close();
} catch (SQLException se) {
se.printStackTrace();
}
}
}
But I getting the following error message :
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SELCET * FROM flight_data' at line 1
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.Util.getInstance(Util.java:381)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1031)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:957)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3376)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3308)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1837)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1961)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2537)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2466)
at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1383)
at services.DBaseReader.readDB(DBaseReader.java:47)
at services.FlightSearchJDBC.main(FlightSearchJDBC.java:10)
So how can I read from the table succefully?
Ehm... what about "SELECT" instead of "SELCET"? :)
I was trying to display the rows in the database using Java. My idea is to sort the rows in the database and display them in 3 columns and infinite rows. This is what I have. When I run it, I couldn't see any output. Where did I go wrong?
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
import java.sql.SQLException;
public class Rows {
public static void main(String[] args) throws SQLException,ClassNotFoundException
{
Connection connection = null;
try {
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/testapp";
String user = "root";
String password = "root";
connection = DriverManager.getConnection(url, user, password);
Statement stmt = connection.createStatement();
String sql = "select * from site order by fname;";
stmt.execute(sql);
} catch (ClassNotFoundException e) {
System.err.println("Could not load database driver!");
} catch (SQLException e) {
e.printStackTrace();
}
finally
{
if (connection != null)
{
connection.close();
}
}
}
}
The database table I have is
datas(id int, fname varchar(20)
Statement stmt = connection.createStatement();
String sql = "select id, fname from site order by fname;";
ResultSet rs=stmt.executeQuery(sql);
while(rs.next()){
int id=rs.getInt("id");
.............
}
Reference: Retrieving and Modifying Values from Result Sets
The code should obtain a ResultsSet and iterate through it.
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/testapp";
String user = "root";
String password = "root";
connection = DriverManager.getConnection(url, user, password);
Statement stmt = connection.createStatement();
//You shouldn't need the semi-colon at the end
String sql = "select * from site order by fname;";
//missing piece
ResultSet rs = stmt.executeQuery(sql);
while (rs.next()) {
int id = rs.getInt("id");
String name = rs.getString("name");
System.out.println(id + "\t" + name);
}