I have a method that contains query like that
public List<Order> getOrders (int customer_id, int count)
{
String sql= "select * from order where customer_id = ? order by order_id DESC FETCH FIRST ? ROWS
ONLY"
}
What i want to do is to list orders according to given input(count).I get error like that
Missing IN or OUT parameter at index:: 2
If I remove the second ? and I write DESC FETCH FIRST 5 ROWS it executes succesfully.I think I could not use salary parameter in DESC FETCH statement.Do you have any idea?
There is indeed no limitation for DESC order in the order_by_clause and row_limiting_clause
you must somehow not set the second parameter ...
Here is working JDBC example with a marked line, that if commented out leads to your exception
def stmt = con.prepareStatement("""select order_id from getOrders
where customer_id = ?
order by order_id DESC
FETCH FIRST ? ROWS ONLY""")
stmt.setInt(1,1001) /* Bind customer_id = 1001 */
stmt.setInt(2,3) /* bind count of rows = 3; uncomment to get java.sql.SQLException: Missing IN or OUT parameter at index:: 2 */
def rs = stmt.executeQuery()
while(rs.next())
{
println "order_id= ${rs.getInt(1)}"
}
Related
I am trying to generate sql query based on user input. There are 4 search fields on the UI:
FIRST_NAME, LAST_NAME, SUBJECT, MARKS
Based on user input I am planning to generate SQL query. Input can be of any combination.
eg: select * from TABLE where FIRST_NAME="some_value";
This query needs to be generated when FIRST_NAME is given and other fields are null
select * from TABLE where FIRST_NAME="some_value" and LAST_NAME="some_value";
This query needs to be generated when FIRST_NAME and LAST_NAME are given and other fields are null
Since there are 4 input fields, number of possible queries that can be generated are 24 (factorial of 4).
One idea is to write if condition for all 24 cases.
Java pseudo code:
String QUERY = "select * from TABLE where ";
if (FIRST_NAME!=null) {
QUERY = QUERY + "FIRST_NAME='use_input_value';"
}
if (LAST_NAME!=null) {
QUERY = QUERY + "LAST_NAME='use_input_value';"
}
if (SUBJECT!=null) {
QUERY = QUERY + "SUBJECT='use_input_value';"
}
if (MARKS!=null) {
QUERY = QUERY + "MARKS='use_input_value';"
}
I am not able to figure out how to generate SQL queries with AND coditions for multiple Input values.
I have been through concepts on dynamically generate sql query but couldn't process further.
Can someone help me on this.
FYI: I have been through How to dynamically generate SQL query based on user's selections?, still not able to generate query string based on user input.
Let's think about what would happen if you just ran the code you wrote and both FIRST_NAME and LAST_NAME are provided. You'll wind up with this:
select * from TABLE where FIRST_NAME='use_input_value';LAST_NAME='use_input_value';
There are two problems here:
The query is syntactically incorrect.
It contains the literals 'use_input_value' instead of the values you want.
To fix the first problem, let's first add and to the start of each expression, and remove the semicolons, something like this:
String QUERY = "select * from TABLE where";
if (FIRST_NAME!=null) {
QUERY = QUERY + " and FIRST_NAME='use_input_value'";
}
Notice the space before the and. We can also remove the space after where.
Now the query with both FIRST_NAME and LAST_NAME will look like this:
select * from TABLE where and FIRST_NAME='use_input_value' and LAST_NAME='use_input_value'
Better but now there's an extra and. We can fix that by adding a dummy always-true condition at the start of the query:
String QUERY = "select * from TABLE where 1=1";
Then we append a semicolon after all the conditions have been evaluated, and we have a valid query:
select * from TABLE where 1=1 and FIRST_NAME='use_input_value' and LAST_NAME='use_input_value';
(It may not be necessary to append the semicolon. Most databases don't require semicolons at the end of a single query like this.)
On to the string literals. You should add a placeholder instead, and simultaneously add the value you want to use to a List.
String QUERY = "select * from TABLE where";
List<String> args = new ArrayList<>();
if (FIRST_NAME!=null) {
QUERY = QUERY + " and FIRST_NAME=?";
args.add(FIRST_NAME);
}
After you've handled all the conditions you'll have a string with N '?' placeholders and a List with N values. At that point just prepare a query from the SQL string and add the placeholders.
PreparedStatement statement = conn.prepareStatement(QUERY);
for (int i = 0; i < args.size(); i++) {
statement.setString(i + 1, args[i]);
}
For some reason columns and parameters are indexed starting at 1 in the JDBC API, so we have to add 1 to i to produce the parameter index.
Then execute the PreparedStatement.
I have a Parameterized query that goes
String stmt = "SELECT * FROM bucket ... ORDER BY $sortCategory DESC";
Then I go:
ParameterizedQuery query = ParameterizedQuery.parameterized(stmt, JsonObject.create().put("sortCategory", "dateUploaded"));
It's not sorting properly. I even printed out query.statementParameters() and it's printing my parameters properly. It only worked when I did a hardcode ("ORDER BY dateUploaded DESC"). Not sure why this is the case.
Why isn't this working?
The problem happens because the query gets translated into something like this:
SELECT * FROM bucket ... ORDER BY 'date' DESC;
Which is probably not making reference to the date column but to the 'date' value.
You can try using an index representing the column position instead of specifying the column name.
String stmt = "SELECT date, column2, column3 FROM bucket ... ORDER BY $sortCategory DESC";
ParameterizedQuery query = ParameterizedQuery.parameterized(stmt, JsonObject.create().put("sortCategory", 1));
I have a query using various joins, and I just need the list of columns which are returned by this query. I done it in java, by asking only one row with rownum=1 and getting column name for value.The problem is if there is no data returned by that query.
For ex.
select * from something
and if there is any data returning by this query then it will return col1,col2,col3.
But if there is no data returned by this query, then it will throw error.
What I need is
Is there any way that I can run
desc (select * from something)
or similar to get list of columns returned by query.
It can be in sql or JAVA. Both methods are acceptable.
In my application, user passes the query, and I can add wrapper to the query but I cant modify it totally.
The flow of application is
query from user -> execute by java and get one row -> return list of columns in the result set.
you can use ResultSetMetaData of resultset
for example :
ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM TABLE2");
ResultSetMetaData rsmd = rs.getMetaData();
int countOfColumns = rsmd.getColumnCount();
for(int i = 1; i <= countOfColumns ; i++ )
System.out.println(rsmd.getColumnName(i));
you could maybe convert your query to a view, you can then see the columns in the view by querying user_tab_columns
select * from user_tab_columns
The Oracle equivalent for information_schema.COLUMNS is USER_TAB_COLS for tables owned by the current user, ALL_TAB_COLS or DBA_TAB_COLS for tables owned by all users.
Tablespace is not equivalent to a schema, neither do you have to provide the tablespace name.
Providing the schema/username would be of use if you want to query ALL_TAB_COLS or DBA_TAB_COLS for columns OF tables owned by a specific user. in your case, I'd imagine the query would look something like:
String sqlStr= "
SELECT column_name
FROM all_tab_cols
WHERE table_name = 'users'
AND owner = ' || +_db+ || '
AND column_name NOT IN ( 'password', 'version', 'id' )
"
Note that with this approach, you risk SQL injection.
Lets say i have four tables i want to read from:
customer
customer_id, customer_name
1 Joe Bolggs
customer_orders
customer_id, order_no
----------------------------
1 1
1 2
1 3
customer_addresses
customer_id address
----------------------------
1 11 waterfall road
1 23 The broadway
customer_tel_no
customer_id number
----------------------------
1 523423423432
1 234342342343
The customer information shown above (for the customer with id=1) is to be stored in a Java object as shown below
public class Customer{
String customer_id;
String customerName;
ArrayList<String> customerOrders;
ArrayList<String> customerAddress;
ArrayList<String> customerTelephoneNumbers;
}
The only way i can think of to get the above information is by using three queries. The reason is that there is a 1:* relationship between the customer table and each of the other tables. To get the data i am doing something like this:
Customer customer = new Customer()
String customerSQL = "Select * from customer where customer_id = ?";
statement = getConnection().prepareStatement(contactsQuery);
statement.setString(1,1);
resultSet = statement.executeQuery();
while (resultSet.next()){
customer.customer_id = resultSet.get(1); //No getters/setters in this example
customer.customerName = resultSet.get(2);
}
String customerOrdersSQL = "Select * from customer_orders where customer_id = ?";
statement = getConnection().prepareStatement(customerOrdersSQL);
statement.setString(1,1);
resultSet = statement.executeQuery();
customer.customerOrders = new ArrayList();
while (resultSet.next()){
customer.customerOrders.add(resultSet.getString(2); // all the order numbers
}
String customerAddressesSQL = "Select * from customer_addresses where customer_id = ?";
statement = getConnection().prepareStatement(customerAddressesSQL );
statement.setString(1,1);
resultSet = statement.executeQuery();
customer.customerAddresses = new ArrayList();
while (resultSet.next()){
customer.customerAddresses.add(resultSet.getString(2); // all the addresses
}
String customerTelSQL = "Select * from customer_tel_no where customer_id = ?";
statement = getConnection().prepareStatement(customerTelSQL);
statement.setString(1,1);
resultSet = statement.executeQuery();
customer.customerTelephoneNumbers = new ArrayList();
while (resultSet.next()){
customer.customerTelephoneNumbers.add(resultSet.getString(2); // all the order numbers
}
The problem with the above is that i am making three calls to the database. Is there a way i can merge the above into a single query please?
I cant see how a join would work because for example, a join between customer and customer_orders will return a customer row for each row in customer_orders. Is there anyway i can merge the above three queries into one?
I would think that something like this would work:
SELECT c.customer_id, c.customer_name, o.order_no, a.address, t.number
FROM customer c LEFT JOIN customer_orders o ON c.customer_id = o.customer_id
LEFT JOIN customer_addresses a ON c.customer_id = a.customer_id
LEFT JOIN customer_tel_no t ON c.customer_id = t.customer_id
WHERE c.customer_id = ?
Then, in your code, after you execute the query:
while (resultSet.next())
{
customer.customerOrders.add(resultSet.getString(3));
customer.customerAddresses.add(resultSet.getString(4));
customer.customerTelephoneNumbers.add(resultSet.getString(5));
}
Of course, this does not take into account the fact that you will have null values along the way, so I'd advise checking for nulls to make sure that you aren't adding a lot of junk to your array lists. Still, that's probably a lot less costly than 3 separate queries.
Nothing prevents you from iterating and processing the joined result into your customer object. If your application is complex enough, you could look into ORM frameworks which would do that for you under the covers. If you are working with JavaEE, have a look at JPA.
use this query and reduce the number of call. And, in while loop process on data.
select customer.customer_id,customer.customer_name,order_no,address,number
from customer,customer_orders,customer_addresses,customer_tel_no
where customer.customer_id = customer_orders.customer_id
AND
customer.customer_id = customer_addresses.customer_id
AND
customer.customer_id = customer_tel_no.customer_id
i have two tables "Table1" with columns user_name,Password and course ID and another table "course" with columns course_id,course_name.I have used the following code to display the course ID from Table1 according to the user_name received from the login page.using ResultSet rs1.now i want to retrieve the course_name from the table "course" according to the course ID receieve from "Table1".for that in the second query pstmt2.setString(1, ); what parameter i should use to get the course_id value from the previous query
HttpSession sess=request.getSession();
String a=(String)sess.getAttribute("user");
String b=(String)sess.getAttribute("pass");
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con=DriverManager.getConnection("jdbc:odbc:ggg");
Statement st = con.createStatement();
String query="select * from Table1 where user_name=?";
PreparedStatement pstmt=con.prepareStatement(query);
pstmt.setString(1,a);
ResultSet rs1=pstmt.executeQuery();
while(rs1.next())
out.println("<h3>COURSE ID: "+rs1.getString("course ID")+"<h3>");
String query2="SELECT * from course where course_id=?";
PreparedStatement pstmt2=con.prepareStatement(query2);
pstmt2.setString(1,);
ResultSet rs2=pstmt2.executeQuery();
while(rs2.next())
{
out.println("<h3>course name: "+rs2.getString("course_name")+"<h3>");
}
why do you go for two turns of database hit, even though you created one time connection object.
modify the query as below
SELECT * from course where course_id = (select course_id from Table1 where user_name=?);
from this query you noneed to give input of courseid also.
No need to hit database twice to get the results that you need. use the query
Select table1.course_id, course.course_name from table1, course where table1.course_id=course_id and table1.user_name=?
This should set the course_id parameter:
pstmt2.setString(1,rs1.getString("course_id"));
Or, as I see the "course_id" column may have a different name in "Table1":
pstmt2.setString(1,rs1.getString("course ID"));
As the other post mentioned there's no need to go to another set of query. Try this example query:
SELECT course.course_id, course.course_name
FROM table1 t1
INNER JOIN course c
ON t1.course_id = c.course_id
WHERE t1.user_name = ?;
Now if you insist your coding the parameter o your pstmt2.setString(1,); is:
pstmt2.setString(1,rs1.getString("course_id")); //or course ID defending on your column name