查詢以下的ratio, 語法是：

select json_array_elements(columnname->'Components'->'Component')#>>'{ratio}' as ratio from tablename;

其中，json_array_elements是把json資料立馬陣列部門取出。#>>是取數組裡的資料

{
    "NAVperCU": "2721431.78",
    "CreationRedemptionUnit": "400000",
    "Fundid1": "510501",
    "MaxCashRatio"
 
: "0.50000",
    "PreTradingDay": "20170328",
    "Recordnum": "500",
    "CashComponent": "-47401.88",
    "Components": {
        "Component": [
            {
                "ratio": "0.10000",
                "sec": "深振業Ａ",
                "amount": "    5100.000",
                "vol": "     600",
                "code"
 
: "000006",
                "mark": "3"
            },
            {
                "ratio": "0.10000",
                "sec": "南  玻Ａ",
                "amount": "    6756.000",
                "vol": "     600",
                "code": "000012",
                "mark": "3"
            
           ]
     }
}

得出結果是

ratio
-----------------------------
0.1
0.1