在Java中将变量添加到sql语句中

Question

我正在尝试在java中编写一个sql语句，该语句在where子句中使用字符串变量。我尝试了多种方法来做到这一点，但它一直告诉我，我没有使用正确的语法。有人可以告诉我正确的方法吗？此查询中的变量是par_id。

  

String sql2 =“SELECT * FROM Tennis1294966077108.container_tbl WHERE parent_id = +”'par_id'“+ ORDER BY creation_time asc”;

Answer 1

使用PreparedStatement

PreparedStatement ps = connection.prepareStatement("SELECT * FROM Tennis1294966077108.container_tbl WHERE parent_id = ? ORDER BY creation_time asc");
ps.setObject(1, par_id);

Answer 2

PreparedStatement ps = connection.prepareStatement(
    "SELECT * FROM Tennis1294966077108.container_tbl " +
    "WHERE parent_id = ? ORDER BY creation_time asc");
ps.setInt(1, par_id); 

Answer 3

String sql2 = "SELECT * FROM Tennis1294966077108.container_tbl WHERE parent_id='"+par_id+"'
ORDER BY creation_time asc";

Answer 4

尝试：

"SELECT * FROM Tennis1294966077108.container_tbl WHERE parent_id = '" 
+ par_id 
+ "' ORDER BY creation_time asc";