postgret的select查询规则如下所示，使用get方式提交请求：
http://localhost:3000/stock_info?select=close,tradingdate&tradingdate=lt.20160429&order=close.desc&limit=15 url中包含表名?select=字段名1,字段名2&过滤条件字段=比较运算符.值&order=排序字段.正序&limit=数量
其中比较运算符包括：
abbreviation meaning
eq equals
gte greater than or equal
gt greater than
lte less than or equal
lt less than
neq not equal
like LIKE operator (use * in place of %)
ilike ILIKE operator (use * in place of %)
in one of a list of values e.g. ?a=in.1,2,3
is checking for exact equality (null,true,false)
@@ full-text search using to_tsquery
@> contains e.g. ?tags=@>.{example, new}
<@ contained in e.g. ?values=<@{1,2,3}
not negates another operator, see below