Reading json array into rows in SQL Server

问题

Given the sample json data below, how can I write a query to pull the array data all in one step? My goal is to have one row for each item in the ActionRecs array (4). My actual json is more complicated but I think this gives a good example of my goal.

declare @json2 nvarchar(max)
set @json2 = '{
    "RequestId": "1",
    "ActionRecs": [
        {
            "Type": "Submit",
            "Employee": "Joe"
        },
        {
            "Type": "Review",
            "Employee": "Betty"
        },
        {
            "Type": "Approve",
            "Employee": "Sam"
        },
        {
            "Type": "Approve",
            "Employee": "Bill"
        }
    ]
}'

SELECT x.*
, JSON_QUERY(@json2, '$.ActionRecs') as ActionArray
from OPENJSON(@json2) 
with (Id varchar(5) '$.RequestId') as x

回答1:

One possible approach is to use OPENJSON()and CROSS APPLY:

DECLARE @json nvarchar(max)
SET @json = '{
    "RequestId": "1",
    "ActionRecs": [
        {
            "Type": "Submit",
            "Employee": "Joe"
        },
        {
            "Type": "Review",
            "Employee": "Betty"
        },
        {
            "Type": "Approve",
            "Employee": "Sam"
        },
        {
            "Type": "Approve",
            "Employee": "Bill"
        }
    ]
}'

SELECT i.Id, a.[Type], a.[Employee]
FROM OPENJSON(@json) 
WITH (
   Id varchar(5) '$.RequestId',
   Actions nvarchar(max) '$.ActionRecs' AS JSON
) AS i
CROSS APPLY (
   SELECT *
   FROM OPENJSON(i.Actions)
   WITH (
      [Type] nvarchar(max) '$.Type',
      [Employee] nvarchar(max) '$.Employee'
   )
) a

Output:

Id  Type    Employee
1   Submit  Joe
1   Review  Betty
1   Approve Sam
1   Approve Bill

来源：https://stackoverflow.com/questions/54371192/reading-json-array-into-rows-in-sql-server