Updates to Chapter 16 per edit
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@ -112,7 +112,7 @@ ORDER BY id;
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-- JSONB CONTAINMENT AND EXISTENCE OPERATORS
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-- Listing 16-6: Demonstrating containment operators
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-- Listing 16-6: Demonstrating the @> containment operator
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-- Does the film JSON value contain the following key/value pair?
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SELECT id, film ->> 'title' AS title,
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@ -120,19 +120,20 @@ SELECT id, film ->> 'title' AS title,
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FROM films
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ORDER BY id;
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-- Using the containment operator in WHERE
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-- Listing 16-7: Using a containment operator in a WHERE clause
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SELECT film ->> 'title' AS title,
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film ->> 'year' AS year
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FROM films
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WHERE film @> '{"title": "The Incredibles"}'::jsonb;
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-- Is the first JSON value contained in the second?
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-- Listing 16-8: Demonstrating the <@ containment operator
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SELECT film ->> 'title' AS title,
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film ->> 'year' AS year
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FROM films
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WHERE '{"title": "The Incredibles"}'::jsonb <@ film;
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-- Listing 16-7: Demonstrating existence operators
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-- Listing 16-9: Demonstrating existence operators
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-- Does the text string exist as a top-level key or array element within the JSON value?
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SELECT film ->> 'title' AS title
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@ -156,7 +157,7 @@ WHERE film ?& '{rating, genre}';
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-- ANALYZING EARTHQUAKE DATA
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-- Listing 16-8: JSON with data on one earthquake
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-- Listing 16-10: JSON with data on one earthquake
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{
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"type": "Feature",
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@ -195,7 +196,7 @@ WHERE film ?& '{rating, genre}';
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"id": "av91018173"
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}
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-- Listing 16-9: Creating and loading an earthquakes table
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-- Listing 16-11: Creating and loading an earthquakes table
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CREATE TABLE earthquakes (
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id integer GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
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@ -209,14 +210,14 @@ CREATE INDEX idx_earthquakes ON earthquakes USING GIN (earthquake);
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SELECT * FROM earthquakes;
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-- Listing 16-10: Retrieving the earthquake time
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-- Listing 16-12: Retrieving the earthquake time
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-- Note that the time is stored in epoch format
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SELECT id, earthquake #>> '{properties, time}' AS time
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FROM earthquakes
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ORDER BY id LIMIT 5;
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-- Listing 16-11: Converting the time value to a timestamp
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-- Listing 16-13: Converting the time value to a timestamp
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SELECT id, earthquake #>> '{properties, time}' as time,
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to_timestamp(
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@ -230,7 +231,7 @@ SHOW timezone;
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SET timezone TO 'US/Eastern';
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SET timezone TO 'UTC';
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-- Listing 16-12: Finding the minimum and maximum earthquake times
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-- Listing 16-14: Finding the minimum and maximum earthquake times
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SELECT min(to_timestamp(
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(earthquake #>> '{properties, time}')::bigint / 1000
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@ -240,7 +241,7 @@ SELECT min(to_timestamp(
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)) AT TIME ZONE 'UTC' AS max_timestamp
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FROM earthquakes;
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-- Listing 16-13: Finding the five earthquakes with the largest magnitude
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-- Listing 16-15: Finding the five earthquakes with the largest magnitude
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SELECT earthquake #>> '{properties, place}' AS place,
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to_timestamp((earthquake #>> '{properties, time}')::bigint / 1000)
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@ -259,7 +260,7 @@ FROM earthquakes
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ORDER BY (earthquake #>> '{properties, mag}')::numeric DESC NULLS LAST
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LIMIT 5;
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-- Listing 16-14: Finding earthquakes with most Did You Feel It? reports
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-- Listing 16-16: Finding earthquakes with most Did You Feel It? reports
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-- https://earthquake.usgs.gov/data/dyfi/
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SELECT earthquake #>> '{properties, place}' AS place,
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@ -271,7 +272,7 @@ FROM earthquakes
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ORDER BY (earthquake #>> '{properties, felt}')::integer DESC NULLS LAST
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LIMIT 5;
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-- Listing 16-15: Extracting the earthquake's location data
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-- Listing 16-17: Extracting the earthquake's location data
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SELECT id,
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earthquake #>> '{geometry, coordinates}' AS coordinates,
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@ -281,7 +282,7 @@ FROM earthquakes
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ORDER BY id
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LIMIT 5;
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-- Listing 16-16: Converting JSON location data to PostGIS geography
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-- Listing 16-18: Converting JSON location data to PostGIS geography
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SELECT ST_SetSRID(
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ST_MakePoint(
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(earthquake #>> '{geometry, coordinates, 0}')::numeric,
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@ -291,7 +292,7 @@ SELECT ST_SetSRID(
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FROM earthquakes
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ORDER BY id;
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-- Listing 16-17: Finding earthquakes within 50 miles of downtown Tulsa, Oklahoma
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-- Listing 16-19: Converting JSON coordinates to a PostGIS geometry column
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-- Add a column of the geography data type
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ALTER TABLE earthquakes ADD COLUMN earthquake_point geography(POINT, 4326);
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@ -308,7 +309,8 @@ SET earthquake_point =
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CREATE INDEX quake_pt_idx ON earthquakes USING GIST (earthquake_point);
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-- Earthquakes 50 miles from Tulsa
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-- Listing 16-20: Finding earthquakes within 50 miles of downtown Tulsa, Oklahoma
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SELECT earthquake #>> '{properties, place}' AS place,
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to_timestamp((earthquake -> 'properties' ->> 'time')::bigint / 1000)
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AT TIME ZONE 'UTC' AS time,
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@ -322,29 +324,30 @@ ORDER BY time;
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-- GENERATING AND MANIPULATING JSON
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-- Listing 16-18: Turning query results into JSON with row_to_json() and json_agg()
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-- Listing 16-21: Turning query results into JSON with to_json()
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-- Convert an entire row from the table
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SELECT to_json(employees) AS json_rows
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FROM employees;
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-- Selected columns from the table (returns key names as f1, f2, etc.)
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-- Listing 16-22: Specifying columns to convert to JSON
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-- Returns key names as f1, f2, etc.
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SELECT to_json(row(emp_id, last_name)) AS json_rows
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FROM employees;
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-- Generating key names with a subquery
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-- Listing 16-23: Generating key names with a subquery
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SELECT to_json(employees) AS json_rows
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FROM (
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SELECT emp_id, last_name AS ln FROM employees
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) AS employees;
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-- Aggregating the rows and converting to JSON
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-- Listing 16-24: Aggregating the rows and converting to JSON
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SELECT json_agg(to_json(employees)) AS json
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FROM (
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SELECT emp_id, last_name AS ln FROM employees
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) AS employees;
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-- Listing 16-19: Adding a top-level key/value pair via concatenation
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-- Listing 16-25: Adding a top-level key/value pair via concatenation
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-- Two examples
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UPDATE films
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@ -358,7 +361,7 @@ WHERE film @> '{"title": "The Incredibles"}'::jsonb;
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SELECT film FROM films -- check the updated data
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WHERE film @> '{"title": "The Incredibles"}'::jsonb;
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-- Listing 16-20: Setting an array value at a path
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-- Listing 16-26: Setting an array value at a path
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UPDATE films
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SET film = jsonb_set(film,
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@ -370,8 +373,7 @@ WHERE film @> '{"title": "Cinema Paradiso"}'::jsonb;
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SELECT film FROM films -- check the updated data
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WHERE film @> '{"title": "Cinema Paradiso"}'::jsonb;
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-- Listing 16-21: Deleting values from JSON
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-- Listing 16-27: Deleting values from JSON
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-- Removes the studio key/value pair from The Incredibles
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UPDATE films
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@ -386,7 +388,7 @@ WHERE film @> '{"title": "Cinema Paradiso"}'::jsonb;
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-- JSON PROCESSING FUNCTIONS
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-- Listing 16-22: Finding the length of an array
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-- Listing 16-28: Finding the length of an array
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SELECT id,
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film ->> 'title' AS title,
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@ -394,7 +396,7 @@ SELECT id,
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FROM films
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ORDER BY id;
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-- Listing 16-23: Returning array elements as rows
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-- Listing 16-29: Returning array elements as rows
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SELECT id,
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jsonb_array_elements(film -> 'genre') AS genre_jsonb,
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@ -402,7 +404,7 @@ SELECT id,
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FROM films
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ORDER BY id;
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-- Listing 16-24: Returning key values from each item in an array
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-- Listing 16-30: Returning key values from each item in an array
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SELECT id,
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jsonb_array_elements(film -> 'characters')
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