I am trying to use the java mysql library but I am having issues using a prepared statement. I am not sure what I am missing. Below is what I have with the MYSQL error attempting to use the prepared statement.
String query = "SELECT id, clicks FROM mailer.links WHERE campaign_id=?";
try {
preparedStatement = connect.prepareStatement(query);
preparedStatement.setInt(1, campaignId);
preparedStatement.execute();
Statement st = connect.createStatement();
// execute the query, and get a java resultset
ResultSet rs = st.executeQuery(query);
I am getting the following error:
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
It works if I do "campaign_id=" + campaignId , but is a SQL injection waiting to happen.
Try this
ResultSet rs = preparedStatement.executeQuery();
PreparedStatement method executeQuery() itself returns a ResultSet object
So assign this to a ResultSet object
ResultSet rs = preparedStatement.executeQuery();
Error:
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
And this error happens because When
ResultSet rs = st.executeQuery(query);
This statement executes it can't find any value in ? operator.
so your query remains this "SELECT id, clicks FROM mailer.links WHERE campaign_id=?"; and this throws a MySQL Syntax Exception.
Related
Here's my query:
select *
from reg
where indexno=?
or tel=?
And here's my code:
Class.forName("com.mysql.cj.jdbc.Driver");
Connection con =DriverManager.getConnection("jdbc:mysql://url","unam","pass");
String query = "select * from reg where indexno= ? or tel=?";
PreparedStatement ps = con.prepareStatement(query);
ps.setString(1, in.getText());
ps.setString(2, tl.getText());
Statement st = con.createStatement();
ResultSet rs = st.executeQuery(query);
Let's take a closer look at what your code is doing.
Connecting to the database:
Connection con =DriverManager.getConnection("jdbc:mysql://url","unam","pass");
Creating the SQL query:
String query = "select * from reg where indexno= ? or tel=?"`;
Creating a prepared statement:
PreparedStatement ps = con.prepareStatement(query);
Setting some bind parameter values:
ps.setString(1, in.getText());
ps.setString(2, tl.getText());
Creating a whole new non-prepared statement (wait, what? Why are we not using the prepared statement we spent some time creating?):
Statement st = con.createStatement();
Using the new non-prepared statement to execute the SQL query.
ResultSet rs = st.executeQuery(query);
As a result of the last two lines, your SQL query is sent straight to the MySQL database. MySQL doesn't understand what the ? marks are for, and hence complains with a syntax error about them.
When handling prepared statements, JDBC drivers will either replace the ? marks with the database's own syntax for bind parameters (unless the database supports ? marks directly, but not all databases do), or put the values directly in the SQL string after suitable escaping of any characters, before they send the SQL to the database. Statements don't support bind parameters, and will just send the SQL string they are given straight to the database.
Your code creates a PreparedStatement and sets two bind parameter values. It seems a shame not to actually use your prepared statement once you've created it. You can get the result set you want out of it by calling ps.executeQuery(). There is no need for the separate Statement you created by calling connection.createStatement().
The fix therefore is to remove the last two lines of the code in your question and add the following line in place of them:
ResultSet rs = ps.executeQuery();
Updated:
so as per the suggestions i changed all the column name to strings and added prepared statements-
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/minor","root","alphabet")) {
Statement st = conn.createStatement();
PreparedStatement stmt= conn.prepareStatement("select * FROM ? where name=? ;");
PreparedStatement stmt2= conn.prepareStatement("select * FROM ? where name=? ;");
stmt.setString(1, day_1);
stmt.setString(2, faculty1);
stmt2.setString(1,day_1);
stmt2.setString(2, faculty2);
ResultSet rs=stmt.executeQuery();
ResultSet rs1= stmt.executeQuery();
The day and faculty is retrieved from input screen, the queries work just fine in mysql workbench but the 'select' keyword goes missing when i try to run it from Java, see the following error-
The faculty1, faculty2 is retrieved from the following-
The database looks like this-
I would recommend to use PreparedStatement instead of Statement, then at least you can bind your variables;
You query select from time_interval from day_selected is not correct, I don't think that it will execute anywhere, you need to have something between select and from, and not two from in one statement.
I am trying to delete the record from my "student" table, the table has two column rollno and student name.
I am using a PreparedStatement but I am getting some error. I could not understand the error. The error is:
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
here is my code
String query = "delete from student where rollno = ?";
PreparedStatement pst = con.prepareStatement(query);
pst.setInt(1, 7);
pst.executeUpdate(query);
Likely you are calling the execute like this:
pst.executeUpdate(query);
This will execute the raw query, without the parameter you set before.
You want to execute the prepared query instead, so just use:
pst.executeUpdate();
session.getAttribute('loginId')//giving 1
ResultSet rs=st.executeQuery("select * from interest where loginid='session.getAttribute('loginId')'");
or
ResultSet rs=st.executeQuery("select * from interest where loginid='session.getAttribute("loginId")'");
this is giving me sql Exception.
what wrong in my query? while-
ResultSet rs=st.executeQuery("select * from interest where loginid='1'");
is running fine.
I cant call this by storing loginId in String Object.
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 'loginId')'' at line 1
Pass in the value returned from getAttribute rather than the literal value session.getAttribute('loginId')
PreparedStatement preparedStatement =
conn.prepareStatement("select * from interest where loginid=?");
preparedStatement.setString(1, session.getAttribute("loginId"));
You have to concat the strings. Not inclusing the parameter in one string:
change to:
ResultSet rs=st.executeQuery("select * from interest where loginid='"+session.getAttribute("loginId")+"'");
Or better use prepared statements. It prevents you for sql injection ans your query will be much more easier to read.
I have a preparedStatement for select query in mySQL.
this is what I wrote:
String sQuery = "SELECT Password FROM test WHERE Email = ?";
st = DB.prepareStatement(sQuery);
st.setString(1, email);
ResultSet rs = st.executeQuery(sQuery);
but i'm getting an exception from the glassfish server that says:
Severe: 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
I don't understand what is the problem.. all the samples i saw, use that syntax..
You must call st.executeQuery(), without the query as argument. The query has already been passed to the statement when it was prepared.
See http://docs.oracle.com/javase/7/docs/api/java/sql/PreparedStatement.html#executeQuery%28%29
st.executeQuery() i.e. no param to executeQuery