How to fetch the json column data from database in SQL Server? - sql-server

Question

I have created a small demo app using .NET 6 with EF core and I am using Serilog to log exceptions into my database.
Everything is working fine but now I want to display the log table details on my view (cshtml).
Current log table columns are:
Message
MessageTemplate
Level
TimeStamp
Exception
LogEvent
ClientIP
I have created a stored procedure to fetch the log details but the LogEvent column contains json data like below:
{
"TimeStamp":"2022-07-23T20:00:55.6987337",
"Level":"Information",
"Message":"Started executing Privacy",
"MessageTemplate":"Started executing Privacy",
"Properties":{
"ActionId":"ba7d94ab-3758-4a4c-a3ef-2bda514a531c",
"ActionName":"Serilog_Demo.Controllers.HomeController.Privacy (Serilog_Demo)",
"RequestId":"SomeRequest",
"RequestPath":"/Home/Privacy",
"ConnectionId":"something",
"MachineName":"Test"
}
}
My goal is to get "Message","TimeStamp","ClientIP", ActionName","MachinName","RequestPath" from above json object. How do I do that? I followed this link
Which shows how to get the JSON data but it seems like I am making some mistake in fetching the records.
Here is my stored procedure:
CREATE PROCEDURE uspGetApplicationLogs
AS
BEGIN
SELECT ClientIP, LogEvent
FROM ApplicationLogs
ORDER BY TimeStamp DESC;
-- this code is not working for me
DECLARE #json NVARCHAR(MAX);
SET #json = (SELECT LogEvent FROM ApplicationLogs)
SELECT *
FROM OPENJSON((SELECT TOP 1 LogEvent FROM ApplicationLogs))
WITH (logDateTime timestamp '$.TimeStamp',
level nvarchar(255) '$.Level',
ActionName NVARCHAR(MAX) '$.Properties.ActionName');
END
And here is my table script, in case if anybody needs it.
CREATE TABLE [dbo].[ApplicationLogs]
(
[Id] [int] IDENTITY(1,1) NOT NULL,
[Message] [nvarchar](max) NULL,
[MessageTemplate] [nvarchar](max) NULL,
[Level] [nvarchar](max) NULL,
[TimeStamp] [datetime] NULL,
[Exception] [nvarchar](max) NULL,
[LogEvent] [nvarchar](max) NULL,
[ClientIP] [nvarchar](max) NULL,
[UserName] [nvarchar](max) NULL,
[ClientAgent] [nvarchar](max) NULL
)
SET IDENTITY_INSERT [dbo].[ApplicationLogs] ON
GO
INSERT INTO [dbo].[ApplicationLogs] ([Id], [Message], [MessageTemplate], [Level], [TimeStamp], [Exception], [LogEvent], [ClientIP], [UserName], [ClientAgent])
VALUES (1, N'Started executing Privacy', N'Started executing Privacy', N'Information', CAST(N'2022-07-23T20:00:55.700' AS DateTime), NULL, N'{"TimeStamp":"2022-07-23T20:00:55.6987337","Level":"Information","Message":"Started executing Privacy","MessageTemplate":"Started executing Privacy","Properties":{"ActionId":"ba7d94ab-3758-4a4c-a3ef-2bda514a531c","ActionName":"Serilog_Demo.Controllers.HomeController.Privacy (Serilog_Demo)","RequestId":"0E:00000004","RequestPath":"/Home/Privacy","ConnectionId":"SomeConnection","MachineName":"Test"}}', NULL, NULL, NULL)
GO
INSERT INTO [dbo].[ApplicationLogs] ([Id], [Message], [MessageTemplate], [Level], [TimeStamp], [Exception], [LogEvent], [ClientIP], [UserName], [ClientAgent])
VALUES (2, N'Attempted to divide by zero.', N'Attempted to divide by zero.', N'Error', CAST(N'2022-07-23T20:00:55.803' AS DateTime), N'System.DivideByZeroException: Attempted to divide by zero.
at Serilog_Demo.Controllers.HomeController.Privacy() in \Sol_Serilog_Demo\Serilog_Demo\Controllers\HomeController.cs:line 24', N'{"TimeStamp":"2022-07-23T20:00:55.8034293","Level":"Error","Message":"Attempted to divide by zero.","MessageTemplate":"Attempted to divide by zero.","Exception":"System.DivideByZeroException: Attempted to divide by zero.\r\n at Serilog_Demo.Controllers.HomeController.Privacy() in \Sol_Serilog_Demo\\Serilog_Demo\\Controllers\\HomeController.cs:line 24","Properties":{"ActionId":"ba7d94ab-3758-4a4c-a3ef-2bda514a531c","ActionName":"Serilog_Demo.Controllers.HomeController.Privacy (Serilog_Demo)","RequestId":"4","RequestPath":"/Home/Privacy","ConnectionId":"VIB38TE","MachineName":"Test"}}', NULL, NULL, NULL)
GO
SET IDENTITY_INSERT [dbo].[ApplicationLogs] OFF
GO
I do not want to deserialize the LogEvent column data at .net end. Can anybody help to parse the JSON and get the log event value from my database?

Answer 1

You need to use CROSS APPLY to feed the JSON column into OPENJSON
CREATE PROCEDURE uspGetApplicationLogs
AS
SET NOCOUNT ON;
SELECT
al.Message,
al.ClientIP,
al.LogEvent,
al.TimeStamp,
j.*
FROM ApplicationLogs al
CROSS APPLY OPENJSON(al.LogEvent)
WITH (
logDateTime datetime2 '$.TimeStamp',
level nvarchar(255) '$.Level',
RequestPath nvarchar(250) '$.Properties.RequestPath',
MachineName nvarchar(250) '$.Properties.MachineName',
ActionName nvarchar(250) '$.Properties.ActionName'
) j
ORDER BY al.TimeStamp DESC;