我有一个典型的带有静态参数的交叉表查询。它适用于createStatement。我想使用preparestatement来查询。
I have a typical crosstab query with static parameters. It works fine with createStatement. I want to use preparestatement to query instead.
String query = "SELECT * FROM crosstab( 'SELECT rowid, a_name, value FROM test WHERE a_name = ''att2'' OR a_name = ''att3'' ORDER BY 1,2' ) AS ct(row_name text, category_1 text, category_2 text, category_3 text);"; PreparedStatement stat = conn.prepareStatement(query); ResultSet rs = stat.getResultSet(); stat.executeQuery(query); rs = stat.getResultSet(); while (rs.next()) { //TODO }但它似乎不起作用。
我得到一个PSQLException - 不能使用带查询的查询方法PreparedStatement上的字符串。
I get a PSQLException - Can't use query methods that take a query string on a PreparedStatement.
我缺少什么想法?
推荐答案你已经陷入混乱的类型层次结构 PreparedStatement extends Statement :
You have fallen for the confusing type hierarchy of PreparedStatement extends Statement:
PreparedStatement 具有相同的执行*(字符串)方法,例如 Statement ,但它们不是应该使用,只需使用无参数 执行*() PreparedStatement 的方法 - - 您已经使用 conn.prepareStatement()给出了实际的查询字符串。
PreparedStatement has the same execute*(String) methods like Statement, but they're not supposed to be used, just use the parameterless execute*() methods of PreparedStatement --- you already have given the actual query string to execute using conn.prepareStatement().
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