Question

我不知道如何为以下查询命中索引：

select * from Cache 
where accountId = 'demo' 
and (? is null or country = ?) 
and (? is null or county = ?) 
and (? is null or province = ?) 
and (? is null or city = ?) 
and (? is null or locality = ?) 
order by createdAt desc

我在cols上有一个orderedGroup索引（accountId，国家/地区，国家/地区，省，城市，地区，createdAt（desc））。如果我删除了isull，它正在工作。也许有另一种方法可以在sql中重写它，以便能够解决空参数？

Answer 1

您可以使用OR expansion重写它：

select * from Cache 
where accountId = 'demo' and ? is null
union all
select * from Cache 
where accountId = 'demo' and city = ?

在Apache中的where条件点燃SQL中处理空值args

1 个答案: