如何为 json 列 SQL Server 2016 创建索引

Question

我有 SQL Server 2016，我正在尝试为视图中的 json 列创建索引。

视图本身是建立在json之上的，如下

SELECT        
    _id, 
    JSON_VALUE(trade, '$.direction') AS direction, 
    JSON_VALUE(trade, '$.entryprice') AS entryprice, 
    JSON_VALUE(trade, '$.exitprice') AS exitprice, 
    JSON_VALUE(trade, '$.potentialtarget') AS potentialtarget, 
    FORMAT(CAST(JSON_VALUE(trade, '$.entrytime') AS datetimeoffset), 'yyyy-MM-dd HH:mm:ss') AS entrytime, 
    FORMAT(CAST(JSON_VALUE(trade, '$.exittime') AS datetimeoffset), 'yyyy-MM-dd HH:mm:ss') AS exittime, 
    JSON_VALUE(trade, '$.maxfavourable') AS maxfavourable, 
    JSON_VALUE(trade, '$.maxagainst') AS maxagainst, 
    JSON_VALUE(trade, '$.signal') AS signal, 
    JSON_VALUE(trade, '$.instrument') AS instrument, 
    JSON_VALUE(trade, '$.account') AS account, 
    JSON_VALUE(trade, '$.quantity') AS quantity, 
    JSON_VALUE(trade, '$.gains') AS gains, 
    JSON_VALUE(trade, '$.hitedge') AS hitedge, 
    JSON_VALUE(trade, '$.RealizedProfitLoss') AS RealizedProfitLoss, 
    JSON_VALUE(trade, '$.CashValue') AS CashValue, 
    JSON_VALUE(trade, '$.BuyingPower') AS BuyingPower, 
    JSON_VALUE(trade, '$.maxagainst1ATR') AS maxagainst1ATR, 
    JSON_VALUE(trade, '$.maxagainst2ATR') AS maxagainst2ATR, 
    JSON_VALUE(trade, '$.Powerbars') AS powerbars, 
    JSON_VALUE(trade, '$.PowerbarsTime[0]') AS PowerbarsTime1, 
    JSON_VALUE(trade, '$.PowerbarsTime[1]') AS PowerbarsTime2, 
    JSON_VALUE(trade, '$.PowerbarsTime[2]') AS PowerbarsTime3, 
    JSON_VALUE(trade, '$.PowerbarsTime[3]') AS PowerbarsTime4, 
    JSON_VALUE(trade, '$.PowerbarsTime[4]') AS PowerbarsTime5, 
    JSON_VALUE(trade, '$.Powerbarsdetails') AS Powerbarsdetails, 
    JSON_VALUE(trade, '$.entrysignal') AS entrysignal, 
    JSON_VALUE(trade, '$.exitsignal') AS exitsignal
FROM            
    dbo.Trades

我正在尝试在 _id 和一些日期时间列上建立索引。我收到一个错误：

索引“NonClusteredIndex-20161124-152652”的创建失败。 (Microsoft.SqlServer.Smo)

执行 Transact-SQL 语句或批处理时发生异常。 (Microsoft.SqlServer.ConnectionInfo)

无法在视图“dbo.vTrades”上创建索引。它没有唯一的聚集索引。 （Microsoft SQL Server，错误：1940）

Answer 1

只需在您的表/视图上创建一个唯一的聚集索引。

CREATE UNIQUE CLUSTERED INDEX cu_indx_ID ON vTrades (id);

那么你应该可以创建你想要的非聚集索引了。

更新：

请务必查看我的答案中的 cmets，以了解有价值的其他详细信息。