如何在存储库中使用函数查询对数据库中的字符串值进行排序?

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英文:

How can I sort string values from DB in repository in functional Queries?

问题

如何在存储库层中使用函数查询对数据库中的字符串值进行排序?

除外可以使用的查询异常。

英文:

How can I sort a string values from DB in repository layer in functional Query?

Exception the query that can be utilized

答案1

得分: 1

以下是翻译好的部分:

可以在JPA查询中使用"order by"查询,例如,有一个名为"Student"的表(实体名称也是"Student"),其中包含学生的年龄和姓名。您需要按姓名对学生列表进行查询。

然后,您可以使用类似以下方式的JPA存储库方法:

List findByOrderByNameDesc();

List findByOrderByNameAsc();

英文:

You can use order by queries in JPA queries,
as an example, there is a table called Student (entity name also Student) with their age and name. You need to query the student list ordered by name.

then you can use a JPA repository method like this

List<Student> findByOrderByNameDesc();

or

List<Student> findByOrderByNameAsc();

答案2

得分: 0

public List getSortedNames() {
String query = "SELECT name FROM my_table ORDER BY name ASC";
List names = new ArrayList<>();

try (Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/my_database", "username", "password");
     Statement stmt = conn.createStatement();
     ResultSet rs = stmt.executeQuery(query)) {

    while (rs.next()) {
        String name = rs.getString("name");
        names.add(name);
    }
} catch (SQLException ex) {
    ex.printStackTrace();
}

return names;

}

英文:
public List&lt;String&gt; getSortedNames() {
String query = &quot;SELECT name FROM my_table ORDER BY name ASC&quot;;
List&lt;String&gt; names = new ArrayList&lt;&gt;();

try (Connection conn = DriverManager.getConnection(&quot;jdbc:mysql://localhost:3306/my_database&quot;, &quot;username&quot;, &quot;password&quot;);
     Statement stmt = conn.createStatement();
     ResultSet rs = stmt.executeQuery(query)) {

    while (rs.next()) {
        String name = rs.getString(&quot;name&quot;);
        names.add(name);
    }
} catch (SQLException ex) {
    ex.printStackTrace();
}

return names;

}

This method retrieves the name column values from the my_table table in ascending order using the ASC keyword in the ORDER BY clause. The retrieved names are stored in a List<String> and returned by the method. Note that you will need to handle any exceptions that may occur during the database access.

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  • 本文由 发表于 2023年3月15日 18:18:26
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