count rows in column by java array in mysql

Question

I have a problem.

There is an array of strings in my java program. In my database i have the strings as well , but they are in ether column a or column b. I need to know in my java program if the element in my array is an element a or an element b. I kind of have an blackout on how to do this.

I have the mysql connection with queries working, no problem there.

The java class currently is :

public static String getCountedDatesTypes(String check) throws ClassNotFoundException {
    String wholeDataModel = "";

    String dates;
    String myDriver = "org.mariadb.jdbc.Driver";
    Class.forName(myDriver);

    Connection con = null;
    Statement st = null;
    ResultSet rs = null;

    String url = "jdbc:mariadb://localhost:3306/house";
    String user = "root";
    String password = "supermanspassword";

    try {

        String tmpblack = "";
        String tmpnormal = "";
        String tmpcheap = "";

        con = DriverManager.getConnection(url, user, password);
        st = con.createStatement();

        String sqlQuery = String.format("select count(black) as black,count(normal) as normal ,count(cheap) as cheap from dates;");
        rs = st.executeQuery(sqlQuery);

        while (rs.next()) {
            String b = rs.getString("black");

            String n = rs.getString("normal");

            String c = rs.getString("cheap");

            System.out.println(b + " " + n + " " + c);

        }

    } catch (SQLException ex) {
        Logger lgr = Logger.getLogger(Mysql_interaction.class.getName());
        lgr.log(Level.SEVERE, ex.getMessage(), ex);

    } finally {
        try {
            if (rs != null) {

                rs.close();
            }
            if (st != null) {
                st.close();
            }
            if (con != null) {
                con.close();
            }

        } catch (SQLException ex) {
            Logger lgr = Logger.getLogger(Mysql_interaction.class.getName());
            lgr.log(Level.WARNING, ex.getMessage(), ex);
        }
    }

Database (super simple):

    MariaDB [house]> select * from dates;
    +----------+----------+----------+
    | black    | normal   | cheap    |
    +----------+----------+----------+
    | 5/5/2015 | NULL     | NULL     |
    | NULL     | 6/5/2015 | NULL     |
    | NULL     | NULL     | 7/5/2015 |
    | NULL     | NULL     | 8/5/2015 |
    +----------+----------+----------+

I need to calculate the prices of the selected dates in the array i have in a java class. I need to know how many of normal and ceap there are. Sof if date 6/5/2015 and 8/5/2015 are provided, i need to be able to know this is 1 normal and 1 cheap.

String check is supposed to be a array of type string later when this works.

Can someone help me please with this problem.

Regards, Rick

Can you please clarify your question? Please post the code you have now and explain how it does not do what you want. — Elliott Frisch
– Elliott Frisch, Commented Mar 22, 2015 at 20:47

hmrojas.p · Accepted Answer · 2015-03-23 18:40:45Z

1

Maybe you need to use a Map, you can use TreeMap or HashMap with another collection to store all values of each type of your Strings, it would be something like this:

...

Map <String, List<String>> map = new HashMap <String, List<String>> ();

List<String> b= new ArrayList<String>();
List<String> n= new ArrayList<String>();
List>String> c= new ArrayList<String>();

String sqlQuery = String.format("select * from dates;");

rs = st.executeQuery(sqlQuery);

while (rs.next()) {
    b.add(rs.getString("black") != null ? rs.getString("black") : "");
    n.add(rs.getString("normal") != null ? rs.getString("normal") : "");
    c.add(rs.getString("cheap") != null ? rs.getString("cheap") : "");
}

map.put("b", b);
map.put("n", n);
map.put("c", c);

...

In this way you can know the type of your Strings.

I hope this information helps you.

Good Luck.

answered Mar 23, 2015 at 18:40

hmrojas.p

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1 Comment

user3046636 Over a year ago

Thank you ! this will work. I will try this out today.

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