: （冒號） 運算符
適用於： 
Databricks SQL Databricks Runtime
使用 JSON 路徑表示式從 JSON 字串擷取內容。
語法
jsonExpr : jsonPath
引數
jsonExprVARIANT：具有有效 JSON 的運算式或STRING表達式。jsonPath：JSON 路徑表達式。
傳回
結果符合的類型 jsonExpr。 如果輸入無效的 JSON，或路徑表示式對 JSON 值無效，則結果為 NULL。
如果擷取的值是未分隔 null 的值，結果就是 NULL 值。
如需有效 JSON 路徑的詳細說明，請參閱 JSON 路徑表達式 。
範例
> SELECT c1:price
FROM VALUES('{ "price": 5 }') AS T(c1);
5
> SELECT c1:['price']::decimal(5,2)
FROM VALUES('{ "price": 5 }') AS T(c1);
5.00
> SELECT c1:item[1].price::double
FROM VALUES('{ "item": [ { "model" : "basic", "price" : 6.12 },
{ "model" : "medium", "price" : 9.24 } ] }') AS T(c1);
9.24
> SELECT c1:item[*].price
FROM VALUES('{ "item": [ { "model" : "basic", "price" : 6.12 },
{ "model" : "medium", "price" : 9.24 } ] }') AS T(c1);
[6.12,9.24]
> SELECT from_json(c1:item[*].price, 'ARRAY<DOUBLE>')[0]
FROM VALUES('{ "item": [ { "model" : "basic", "price" : 6.12 },
{ "model" : "medium", "price" : 9.24 } ] }') AS T(c1);
6.12
> SELECT from_json(c1:item[*], 'ARRAY<STRUCT<model STRING, price DOUBLE>>')
FROM VALUES('{ "item": [ { "model" : "basic", "price" : 6.12 },
{ "model" : "medium", "price" : 9.24 } ] }') AS T(c1);
[{"model":"basic","price":6.12},{"model":"medium","price":9.24}]
> SELECT inline(from_json(c1:item[*], 'ARRAY<STRUCT<model STRING, price DOUBLE>>'))
FROM VALUES('{ "item": [ { "model" : "basic", "price" : 6.12 },
{ "model" : "medium", "price" : 9.24 } ] }') AS T(c1);
basic 6.12
medium 9.24
-- Examples with VARIANT expressions.
> SELECT PARSE_JSON('{ "price": 5 }'):price
5
> SELECT PARSE_JSON('{ "price": 5 }'):price::decimal(5,2)
5.00
> SELECT PARSE_JSON('{ "item": [ { "model" : "basic", "price" : 6.12 },
{ "model" : "medium", "price" : 9.24 } ] }'):item[1].price::double
9.24