JAVA: get cell from table of mysql

Question

I get a parameter is called 'id' in my function and want to print the cell of the name of this id row.

for example:

this is my table:

id     name        email
1      alon     [email protected]

I send to my function: func(1), so I want it to print 'alon'.

this is what I tried:

static final String url = "jdbc:mysql://localhost:3306/database_alon";
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection(url, "root", "Admin");
String query_txt = "SELECT * FROM authors WHERE id = " + id;
Statement ps2 = con.createStatement();
ResultSet my_rs = ps2.executeQuery(query_txt);
System.out.println(my_rs.getString("name"));
con.close;

Rohit Jain · Accepted Answer · 2012-11-30 23:45:03Z

2

Everything is fine, but just one problem. You need to move your ResultSet cursor to the first row before fetching any values: -

Use: -

ResultSet my_rs = ps2.executeQuery(query_txt);
while (my_rs.next()) {
    System.out.println(my_rs.getString("name"));
}

As a side note, consider using PreparedStatement to avoid getting attacked by SQL Injection.

Here's how you use it: -

PreparedStatement ps2 = con.prepareStatement("SELECT * FROM authors WHERE id = ?");
ps2.setInt(1, id);
ResultSet my_rs = ps2.executeQuery();

while (my_rs.next()) {
    System.out.println(my_rs.getString("name"));
}

edited Nov 30, 2012 at 23:45

answered Nov 30, 2012 at 23:39

Rohit Jain

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Comments

Reimeus · Accepted Answer · 2012-11-30 23:39:36Z

2

You need to use ResultSet.next() to navigate into the returned data:

if (my_rs.next()) {
  System.out.println(my_rs.getString("name"));
}

answered Nov 30, 2012 at 23:39

Reimeus

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Comments

Nick · Accepted Answer · 2012-11-30 23:41:11Z

2

Call my_rs.next(), which will move the ResultSet cursor onto the first row (which you are extracting data out of).
If this is a real application, use PreparedStatements instead of generic Statements. This is an extremely important matter of security if you plan on using user input in SQL queries.

answered Nov 30, 2012 at 23:41

Nick

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