java - 带有可变参数的简单查询

Question

我有三个查询，我想将它们合并为一个查询，该查询可以接受可变长度的 WHERE 参数；我一辈子都不记得如何做到这一点。

PreparedStatement queryOne = connection.prepareStatement
("SELECT columnOne, columnTwo, columnThree FROM tableOne WHERE columnOne = ?;" );

PreparedStatement queryTwo = connection.prepareStatement
("SELECT columnOne, columnTwo, columnThree FROM tableOne WHERE columnTwo = ?;" );

PreparedStatement queryThree = connection.prepareStatement
("SELECT columnOne, columnTwo, columnThree FROM tableOne WHERE columnOne = ? AND columnTwo = ?;" );

Answer 1

所有三个查询都从同一个表中选择相同的列，因此可以在一个语句中轻松完成它们的并集:

SELECT columnOne, columnTwo, columnThree 
  FROM tableOne 
 WHERE columnOne = ?
    or columnTwo = ?
    or (columnOne = ? AND columnTwo = ?)