java如何在与给定值相同的记录中找到值

Question

我试图给MySQL一个值，我希望它搜索记录，找到具有该值的记录，并在同一记录中获得一个特定值（在本例中为ID）

Example:

|ID|Name|

ID is "5" and name is "Lapino"

我如何将“Lapino”传递给MySQL，让它搜索该记录并返回ID

谢谢， L

Answer 1

必须使用PreparedStatement执行SELECTSQL语句：

Connection conn = /*defined elsewhere*/;
String name = /*defined elsewhere*/;

int id;
String sql = "select ID from MyTable where Name = ?";
try (PreparedStatement stmt = conn.prepareStatement(sql)) {
    stmt.setString(1, name);
    try (ResultSet rs = stmt.executeQuery()) {
        if (! rs.next())
            throw new IllegalArgumentException("Not found: " + name);
        id = rs.getInt("ID");
        if (rs.next())
            throw new IllegalArgumentException("Multiple rows found: " + name);
    }
}
System.out.println(id); // Yay!

Answer 2

如果我理解正确，您想找到ID值与请求值匹配的记录吗？要查找ID等于1234的记录，请执行以下操作：

SELECT * FROM tbl WHERE ID = 1234

Answer 3

首先创建一个jdbc连接，然后使用语句执行所需的查询

    Connection conn =
   DriverManager.getConnection("jdbc:mysql://localhost/test?" +
                               "user=vikas&password=123");
    Statement stmt = conn.createStatement();
    ResultSet   rs = stmt.executeQuery("SELECT * FROM table WHERE ID=some_val");