Basic JSON queries

Here is the code I used in the video on Basic JSON queries.

/*********************
basic JSON queries 
*********************/

--create a table with Json as a datatype
Create table JsonTest
(
  testID serial primary key,
  test Json
);

--insert some records
Insert into JsonTest(test)
Values('{"testname" : "testOne", "testnumber" : 123, "testdate" :"2019-05-02"}'),
('{"testname" : "testtwo", "testnumber" : 234, "testdate" :"2019-05-08"}'),
('{"testname" : "testthree", "testnumber" : 345, "testdate" :"2019-05-12"}');


--query the value of a field
Select test ->>'testname' as "name" from jsontest;

--creates an array of sorts putting each element on its own row
Select Json_each(test) from Jsontest;

--returns the keys in the Json record
Select Distinct Json_object_keys(test) from jsontest;

--gets tne count of tests
Select count(cast (test ->> 'testnumber' as integer)) from Jsontest;

--returns the results of a query as Json
--double click the results to get a little dialog box
--copy and paste to a text editor to see the full results
with j as
(
 Select personfirstname, personlastname, positionname
    from person
    join employee using (personkey)
    join employeeposition using (employeekey)
 join jobposition using (positionkey)
)
Select json_agg(j) from j;