如何在 java 中执行复合 sql 查询？

Question

How can I execute the following query and retrieve a result via prepared statement:

INSERT INTO vcVisitors (sid) VALUES (?); SELECT LAST_INSERT_ID();

Is there a way to execute both two statements at once?

I've tried to do the following:

Connection con = DbManager.getConnection();
PreparedStatement ps = con.PrepareStatement(
     "INSERT INTO vcVisitors (sid) VALUES (?); SELECT LAST_INSERT_ID();");
ps.setInt(1, 10);
ResultSet rs = ps.exequteQuery();
rs.next();
return rs.getInt("LAST_INSERT_ID()");

but it gives me an error that executeQuery can't execute such a query, I've also tried to replace executeQuery by the following:

ps.execute();
rs = ps.getResultSet();

but it gives me SQL syntax error:

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 'SELECT LAST_INSERT_ID()' at line 1

but there are no problems with executing query directly from mysql console.

Answer 1

While updating (inserting) data use executeUpdate instead of executeQuery . Try executing SELECT LAST_INSERT_ID() as another query.

But it is not portable query. I suggest using Statement.getGeneratedKeys instead. Please look here: JDBC (MySQL) Retrieving AUTO_INCREMENT Column Values .

Here is an example of properly used LAST_INSERT_ID():

    Statement stmt = null;
   ResultSet rs = null;

   try {

    //
    // Create a Statement instance that we can use for
    // 'normal' result sets.

    stmt = conn.createStatement();

    //
    // Issue the DDL queries for the table for this example
    //

    stmt.executeUpdate("DROP TABLE IF EXISTS autoIncTutorial");
    stmt.executeUpdate(
            "CREATE TABLE autoIncTutorial ("
            + "priKey INT NOT NULL AUTO_INCREMENT, "
            + "dataField VARCHAR(64), PRIMARY KEY (priKey))");

    //
    // Insert one row that will generate an AUTO INCREMENT
    // key in the 'priKey' field
    //

    stmt.executeUpdate(
            "INSERT INTO autoIncTutorial (dataField) "
            + "values ('Can I Get the Auto Increment Field?')");

    //
    // Use the MySQL LAST_INSERT_ID()
    // function to do the same thing as getGeneratedKeys()
    //

    int autoIncKeyFromFunc = -1;
    rs = stmt.executeQuery("SELECT LAST_INSERT_ID()");

    if (rs.next()) {
        autoIncKeyFromFunc = rs.getInt(1);
    } else {
        // throw an exception from here
    }

    rs.close();

    System.out.println("Key returned from " +
                       "'SELECT LAST_INSERT_ID()': " +
                       autoIncKeyFromFunc);

} finally {

    if (rs != null) {
        try {
            rs.close();
        } catch (SQLException ex) {
            // ignore
        }
    }

    if (stmt != null) {
        try {
            stmt.close();
        } catch (SQLException ex) {
            // ignore
        }
    }
}

and here the same with getGeneratedKeys:

     Statement stmt = null;
   ResultSet rs = null;

   try {

    //
    // Create a Statement instance that we can use for
    // 'normal' result sets assuming you have a
    // Connection 'conn' to a MySQL database already
    // available

    stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY,
                                java.sql.ResultSet.CONCUR_UPDATABLE);

    //
    // Issue the DDL queries for the table for this example
    //

    stmt.executeUpdate("DROP TABLE IF EXISTS autoIncTutorial");
    stmt.executeUpdate(
            "CREATE TABLE autoIncTutorial ("
            + "priKey INT NOT NULL AUTO_INCREMENT, "
            + "dataField VARCHAR(64), PRIMARY KEY (priKey))");

    //
    // Insert one row that will generate an AUTO INCREMENT
    // key in the 'priKey' field
    //

    stmt.executeUpdate(
            "INSERT INTO autoIncTutorial (dataField) "
            + "values ('Can I Get the Auto Increment Field?')",
            Statement.RETURN_GENERATED_KEYS);

    //
    // Example of using Statement.getGeneratedKeys()
    // to retrieve the value of an auto-increment
    // value
    //

    int autoIncKeyFromApi = -1;

    rs = stmt.getGeneratedKeys();

    if (rs.next()) {
        autoIncKeyFromApi = rs.getInt(1);
    } else {

        // throw an exception from here
    }

    rs.close();

    rs = null;

    System.out.println("Key returned from getGeneratedKeys():"
        + autoIncKeyFromApi);
} finally {

    if (rs != null) {
        try {
            rs.close();
        } catch (SQLException ex) {
            // ignore
        }
    }

    if (stmt != null) {
        try {
            stmt.close();
        } catch (SQLException ex) {
            // ignore
        }
    }
}

Answer 2

As others have already said, this won't work. But it looks like you just want to get the ID of the last insert. To achieve that, you can use the getGeneratedKeys() method of theStatement class.

Answer 3

Try with:

Connection con = DbManager.getConnection();
int lastid = 0;

PreparedStatement psInsert = con.PrepareStatement(
     "INSERT INTO vcVisitors (sid) VALUES (?)");
psInsert.setInt(1, 10);
psInsert.executeUpdate();

PreparedStatement psSelect = 
    con.PrepareStatement("SELECT LAST_INSERT_ID() AS lastid");
ResultSet rs = psSelect.executeQuery();
rs.next();

lastid = rs.getInt("lastid");

rs.close();
psInsert.close();
psSelect.close();
con.close();
return lastid;