SQL Server JSON_VALUE syntax - json

Question

I created a SQL Server Table with 25 columns. One of my columns is actually JSON text, stored as nvarchar(max).
Now I need to able to query this JSON column and parse out the various attributes. I have tried applying JSON_VALUE to my column but am doing something wrong; my query runs but returns NULL for all the values.
The JSON itself looks like:
[
{
"lineName":"GHjr",
"pipeDiameter":"12",
"pipeLength":"52000",
"pressure":"15",
"volume":"107"
},
{
"lineName":"Ks3R",
"pipeDiameter":"9",
"pipeLength":"40000",
"pressure":"15",
"volume":"80"
}
]
The SQL I am using is:
select
DOC_ID, LINE_SPECS,
JSON_VALUE(LINE_SPECS, '$.lineName') as line_name,
JSON_VALUE(LINE_SPECS, '$.pipe_Diameter') as diameter
from dbo.MY_TEST_DOCS
where ISJSON(LINE_SPECS) > 0
and len(LINE_SPECS) > 3
However, my 2 "parsed" columns are returning all NULL. How do I parse the five attributes from this column?

Answer 1

Without the [] ISJSON is returning false
With [] ISJSON retuns true
Without the [] JSON_VALUE returns NULLs
With [] JSON_VALUE returns values
dbfddle.uk has sql server 2016 available....
create table test (LINE_SPECS nvarchar(max));
insert into test values (N'
{
"lineName":"GHjr",
"pipeDiameter":"12",
"pipeLength":"52000",
"pressure":"15",
"volume":"107"
},
{
"lineName":"Ks3R",
"pipeDiameter":"9",
"pipeLength":"40000",
"pressure":"15",
"volume":"80"
}
');
select *
from test
where ISJSON(LINE_SPECS) > 0
;
GO
| LINE_SPECS |
| :--------- |
select
JSON_VALUE(LINE_SPECS, '$.lineName') as line_name
, JSON_VALUE(LINE_SPECS, '$.pipeDiameter') as diameter
from test
;
GO
line_name | diameter
:-------- | :-------
GHjr | 12
dbfiddle here