如果您正在寻找自己的特殊用途语言,请查看JSONiq,专门为JSON数据模型设计的查询语言。下面是从Wikipedia采取了一个简单的例子:
for $p in collection("persons")
where $p.age gt 20
let $home := $p.phoneNumber[][$$.type eq "home"].number
group by $area := substring-before($home, " ")
return
{
"area code" : $area,
"count" : count($p)
}
如果你想类似的功能,以SQL JOIN子句,看看下面的example:
let $stores :=
[
{ "store number" : 1, "state" : "MA" },
{ "store number" : 2, "state" : "MA" },
{ "store number" : 3, "state" : "CA" },
{ "store number" : 4, "state" : "CA" }
]
let $sales := [
{ "product" : "broiler", "store number" : 1, "quantity" : 20 },
{ "product" : "toaster", "store number" : 2, "quantity" : 100 },
{ "product" : "toaster", "store number" : 2, "quantity" : 50 },
{ "product" : "toaster", "store number" : 3, "quantity" : 50 },
{ "product" : "blender", "store number" : 3, "quantity" : 100 },
{ "product" : "blender", "store number" : 3, "quantity" : 150 },
{ "product" : "socks", "store number" : 1, "quantity" : 500 },
{ "product" : "socks", "store number" : 2, "quantity" : 10 },
{ "product" : "shirt", "store number" : 3, "quantity" : 10 }
]
let $join :=
for $store in $stores[], $sale in $sales[]
where $store."store number" = $sale."store number"
return {
"nb" : $store."store number",
"state" : $store.state,
"sold" : $sale.product
}
return [$join]
-> [
{ "nb" : 1, "state" : "MA", "sold" : "broiler" },
{ "nb" : 1, "state" : "MA", "sold" : "socks" },
{ "nb" : 2, "state" : "MA", "sold" : "toaster" },
{ "nb" : 2, "state" : "MA", "sold" : "toaster" },
{ "nb" : 2, "state" : "MA", "sold" : "socks" },
{ "nb" : 3, "state" : "CA", "sold" : "toaster" },
{ "nb" : 3, "state" : "CA", "sold" : "blender" },
{ "nb" : 3, "state" : "CA", "sold" : "blender" },
{ "nb" : 3, "state" : "CA", "sold" : "shirt" }
]
您正在使用什么语言来从查询'json'数据? – ode2k
因此,数据在DB中以json格式存储? –
请更新您的文章,并回答问题@ ode2k问题,再加上一些细节。你用什么语言查询json数据? –