select子句中参数的未知数据类型错误

Question

我想使用以下代码查询我的数据库（H2）：

PreparedStatement x = connection.prepareStatement("INSERT INTO tree(ancestor, desc) (select ancestor,? from tree where desc = ? union all select ?,? )");
x.setInt(1,99219);
x.setInt(2,4);
x.setInt(3,99219);
x.setInt(4,99219);

但它不起作用，我收到以下错误：

org.h2.jdbc.JdbcSQLException: Unknown data type: "?, ?"; SQL statement:insert into tree(ancestor, desc) (select ancestor,? from tree where desc = ? union all select ?,? ) [50004-192]

在控制台中执行查询（不使用JDBC）可以正常工作。这段代码有什么问题？

Answer 1

"INSERT INTO tree(ancestor, desc) (select ancestor,? from tree where desc = ? union all select ?,? )"

此SQL语句不完整。在此之后，它正在调整FROM部分：

union all select ?,?

Answer 2

UNION select返回的列必须按类型匹配第一个选择中的列。你可以做一个明确的演员。