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POWhy I didn't get results when adding Where clause to my query?
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  1. POWhy I didn't get results when adding Where clause to my query?
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    copied!<p>I'm using Mysql JDBC driver.. but I have some problem.. </p> <p>the problem is when I use <code>SELECT</code> Query in java source code.</p> <p>When I use this query: </p> <pre><code>select * from [name of table] </code></pre> <p>I've gotten result of query from DB successfully.</p> <p>but when I use this query: </p> <pre><code> select * from student where (substring(stu_name,0,1)&gt;= '가' and substring(stu_name,0,1) &lt; '나') ; </code></pre> <p>I've not gotten result of query from DB..</p> <p>The difference thing is just that using <code>where</code> or not.</p> <p><strong>What's the problem?</strong></p> <p><strong>How can I solve this problem?</strong></p> <p>this is my code below</p> <p>this query isn't working</p> <pre><code>select * from student where (substring(stu_name,0,1)&gt;= '가' and substring(stu_name,0,1) &lt; '나') ; </code></pre> <p>this query is working very well</p> <pre><code>select * from student; </code></pre> <p>The difference thing is just only query information .. rest of the source code is the same absolutely</p> <hr> <p>I added my java source code public class Center {</p> <pre><code>/** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub String sql = "select * from student where (substring(stu_name,0,1)&gt;= '가' and substring(stu_name,0,1) &lt; '나') "; String url = "jdbc:mysql://localhost:3306/test"; String driverName = "com.mysql.jdbc.Driver"; String id = "root"; String password = "jsyun0415"; Connection con = null; PreparedStatement prepareState = null; Statement stmt = null; ResultSet rs = null; ArrayList&lt;String&gt; list = new ArrayList&lt;String&gt;(); ArrayList&lt;String&gt; list_second = new ArrayList&lt;String&gt;(); try { Class.forName(driverName); } catch (ClassNotFoundException e) { System.out.println("Failed to load JDBC driver.."); e.printStackTrace(); return; } try { con = DriverManager.getConnection(url, id, password); stmt = con.createStatement(); rs = stmt.executeQuery(sql); while (rs.next()) { list.add(rs.getNString("stu_no")); list_second.add(rs.getNString("stu_ename")); } //test = list.get(2); } catch (SQLException sqex) { System.out.println("SQLException: " + sqex.getMessage()); System.out.println("SQLState: " + sqex.getSQLState()); } finally { try { if (stmt != null) stmt.close(); if (con != null) con.close(); if (rs != null) rs.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } </code></pre> <p>}</p>
 

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