带有AND

Question

我有这种结构的SQL查询：

......
......
where a.id=#{x} AND b.id!=#{x}
......

现在我想更改此查询以接受x的值列表。我应该如何为此编写foreach循环？

Answer 1

我会将您的WHERE更改为表单 SELECT ... FROM ... WHERE a.id IN (...x...) AND b.id NOT IN (...x...)

然后，您的注释或XML将包含：

  SELECT ...
  FROM ...
  WHERE a.id IN <foreach item="item" index="index" collection="x"
        open="(" separator="," close=")">
          #{item}
    </foreach>
  AND b.id NOT IN <foreach item="item" index="index" collection="x"
        open="(" separator="," close=")">
          #{item}
    </foreach>

这将产生更高效的SQL。