How to extract specific text from column - sql

Question

I am using SQL Server 2016 where I am loading JSON Response in one of the nvarchar(max) type column.
Now I want to create a derived column or maybe even a view that will find the particular value in that complete JSON Response and display only that in the new derived column.
Example:
**Complete_JSON_Repsone** --> this is SQL column
{"result":{"banner_image_light":"","country":"USA","parent":"","notes":"","stock_symbol":"","u_op_dev_version":"","u_restriciton":"No","discount":"","sys_id":"7a2c008c1b07ac50a62cea0ce54bcbe8","market_cap":"0","customer":"false"}}
I tried the below query, but it's not giving the expected results it prints out everything after sys_id:
SELECT
Substring (
a.Complete_JSON_Repsone,
Charindex( '"sys_id":', Complete_JSON_Repsone) + 1,
Len(Complete_JSON_Repsone)
) AS [Sys_Idd]
FROM <table-name> a
Current output (actual result):
Sys_Idd
sys_id":"7a2c008c1b07ac50a62cea0ce54bcbe8","market_cap":"0","customer":"false"}}
Expected output:
Sys_Idd
7a2c008c1b07ac50a62cea0ce54bcbe8
UPDATE
Sample Input :
Create table dbo.log1
(
Id varchar(50),
Complete_JSON_Response nvarchar(max),
Sys_Id varchar(50)
)
insert into dbo.log1 (Id,Complete_JSON_Response)
values ('S1','{"result":{"banner_image_light":"","country":"USA","parent":"","notes":"","stock_symbol":"","u_op_dev_version":"","u_restriciton":"No","discount":"","sys_id":"7a2c008c1b07ac50a62cea0ce54bcbe8","market_cap":"0","customer":"false"}}')
,('S2','{"result":{"banner_image_light":"","country":"Aus","parent":"","notes":"","stock_symbol":"","u_op_prod_version":"","u_restriciton":"No","discount":"","sys_id":"5b2c008c1b07ac50a62cea0ce54bcbe8","market_cap":"1","customer":"TRUE"}}')
select * from dbo.log1
Above select query prints, NULL value for Sys_id column as value for that column in not inserted initially. what I want in expected output is that instead of NULL it should populate(derive) only sys_id value from Complete_JSON_Response column to Sys_id column
Expected output:
Id Sys_Id
S1 7a2c008c1b07ac50a62cea0ce54bcbe8
S2 5b2c008c1b07ac50a62cea0ce54bcbe8

Answer 1

SQL Server 2016 supports JSON, so you may try to use JSON_VALUE():
SELECT JSON_VALUE(Complete_JSON_Response, '$.result.sys_id') AS sys_id
FROM (VALUES
(N'{
"result":{
"banner_image_light":"",
"country":"USA",
"parent":"",
"notes":"",
"stock_symbol":"",
"u_op_dev_version":"",
"u_restriciton":"No",
"discount":"",
"sys_id":"7a2c008c1b07ac50a62cea0ce54bcbe8",
"market_cap":"0",
"customer":"false"
}
}')
) a (Complete_JSON_Response)
As an additional option, you may create a simplified UDF with a recursive search:
CREATE FUNCTION dbo.ParseJson (
#json nvarchar(max),
#key nvarchar(max)
)
RETURNS #ResultTable TABLE (
[value] nvarchar(max)
)
AS
BEGIN
;WITH rCTE AS (
SELECT
CONVERT(nvarchar(max), N'$') COLLATE DATABASE_DEFAULT AS [path],
CONVERT(nvarchar(max), JSON_QUERY(#json, '$')) COLLATE DATABASE_DEFAULT AS [value]
UNION ALL
SELECT
CONVERT(nvarchar(max), c.[key]) COLLATE DATABASE_DEFAULT,
CONVERT(nvarchar(max), c.[value]) COLLATE DATABASE_DEFAULT
FROM rCTE r
CROSS APPLY OPENJSON(r.[value]) c
WHERE ISJSON(r.[value]) = 1
)
INSERT INTO #ResultTable ([value])
SELECT [value]
FROM rCTE
WHERE (ISJSON([value]) = 0) AND (path = #key)
RETURN
END
Statement:
DECLARE #json nvarchar(max) = N'
{
"result":{
"banner_image_light":"",
"country":"USA",
"parent":"",
"notes":"",
"stock_symbol":"",
"u_op_dev_version":"",
"u_restriciton":"No",
"discount":"",
"sys_id":"7a2c008c1b07ac50a62cea0ce54bcbe8",
"market_cap":"0",
"customer":"false"
},
"result2":{
"sys_id":"xxxx008c1b07ac50a62cea0ce54bcbe8"
}
}
'
SELECT j.[value] AS sys_id
FROM (VALUES (#json)) a (Complete_JSON_Response)
OUTER APPLY dbo.ParseJson(a.Complete_JSON_Response, 'sys_id') j
Result:
sys_id
--------------------------------
xxxx008c1b07ac50a62cea0ce54bcbe8
7a2c008c1b07ac50a62cea0ce54bcbe8

Answer 2

You can use a function. It may lead some performance issues but works fine.
select
'{"result":{"banner_image_light":"","country":"USA","parent":"","notes":"","stock_symbol":"","u_op_dev_version":"","u_restriciton":"No","discount":"","sys_id":"7a2c008c1b07ac50a62cea0ce54bcbe8","market_cap":"0","customer":"false"}}' json
into tmp_json
CREATE FUNCTION dbo.trialFnc(
#json nvarchar(max),
#key nvarchar(255)
)
RETURNS nvarchar(255)
AS
BEGIN
declare #txt1 nvarchar(max) = right(#json, len(#json) - (charindex(#key, #json)) + 1 - len(#key) - 3)
declare #txt2 nvarchar(max) = left(#txt1, charindex('"', #txt1) - 1)
RETURN #txt2
END;
select
dbo.trialFnc(json, 'country') country
, dbo.trialFnc(json, 'sys_id') sys_id
from tmp_json
It will return you this:
country
sys_id
USA
7a2c008c1b07ac50a62cea0ce54bcbe8