mirror of https://github.com/citusdata/citus.git
329 lines
6.2 KiB
SQL
329 lines
6.2 KiB
SQL
-- Complex nested CTEs
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CREATE SCHEMA with_nested;
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SET search_path tO with_nested, public;
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CREATE TABLE with_nested.local_users (user_id int, event_type int);
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INSERT INTO local_users VALUES (0, 0), (1, 4), (1, 7), (2, 1), (3, 3), (5, 4), (6, 2), (10, 7);
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-- Can refer to outer CTE because it is recursively planned first
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WITH cte_1 AS (
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SELECT DISTINCT user_id FROM users_table
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),
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cte_2 AS (
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WITH cte_1_1 AS (
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SELECT * FROM cte_1 WHERE user_id > 1
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)
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SELECT * FROM cte_1_1 WHERE user_id < 3
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)
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SELECT user_id FROM cte_2 LIMIT 1;
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-- Nested CTEs
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WITH users_events AS (
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WITH users_events_2 AS (
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SELECT
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users_table.user_id as user_id,
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events_table.event_type as event_type
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FROM
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users_table,
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events_table
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WHERE
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users_table.user_id = events_table.user_id
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GROUP BY
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users_table.user_id,
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events_table.event_type
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)
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SELECT
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u_events.user_id, events_table.event_type
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FROM
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users_events_2 as u_events,
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events_table
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WHERE
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u_events.user_id = events_table.user_id
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)
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SELECT
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*
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FROM
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users_events
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ORDER BY
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1, 2
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LIMIT 20;
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-- Nested CTEs
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WITH users_events AS (
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WITH users_events AS (
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WITH users_events AS (
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WITH users_events AS (
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WITH users_events AS (
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WITH users_events AS (
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WITH users_events AS (
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SELECT
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users_table.user_id as user_id,
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events_table.event_type as event_type
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FROM
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users_table,
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events_table
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WHERE
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users_table.user_id = events_table.user_id
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GROUP BY
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users_table.user_id,
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events_table.event_type
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)
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SELECT
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uid, event_type, value_2, value_3
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FROM
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(
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(
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SELECT
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user_id as uid
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FROM
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users_events
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) users
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join
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events_table
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on
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users.uid = events_table.event_type
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) a
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)
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SELECT
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*
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FROM
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users_events
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ORDER BY
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1, 3, 2, 4
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LIMIT 100
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)
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SELECT
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*
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FROM
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users_events
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LIMIT 90
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)
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SELECT
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*
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FROM
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users_events
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LIMIT 50
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)
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SELECT
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uid, event_type, value_2, sum(value_3) as sum_3
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FROM
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users_events
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GROUP BY
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1, 2, 3
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LIMIT 40
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)
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SELECT
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uid, event_type, sum(value_2) as sum_2, sum(sum_3) as sum_3
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FROM
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users_events
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GROUP BY
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1, 2
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LIMIT 30
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)
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SELECT
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uid, avg(event_type), sum(sum_2), sum(sum_3)
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FROM
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users_events
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GROUP BY
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1;
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-- Nested CTEs
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WITH users_events AS (
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-- router select query
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WITH users_events_1 AS (
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SELECT
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*
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FROM
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users_table
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WHERE
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user_id = 1
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),
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-- real-time select query
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users_events_2_3 AS (
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SELECT
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*
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FROM
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users_table
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WHERE
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user_id = 2
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OR
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user_id = 3
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),
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-- router select query
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-- sub CTE is a real-time executor query but the top level is router select
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users_events_4 AS (
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WITH users_events_4_5 AS (
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SELECT
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*
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FROM
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users_table
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WHERE
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user_id = 4
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OR
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user_id = 5
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)
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SELECT
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*
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FROM
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users_events_4_5
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WHERE
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user_id = 4
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),
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-- merge all the results from CTEs
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merged_users AS (
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SELECT
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*
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FROM
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users_events_1
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UNION
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SELECT
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*
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FROM
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users_events_2_3
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UNION
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SELECT
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*
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FROM
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users_events_4
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)
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SELECT
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*
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FROM
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merged_users
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)
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SELECT
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*
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FROM
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users_events
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ORDER BY
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1, 2, 3, 4, 5, 6
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LIMIT
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20;
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-- Nested CTEs - joined with local table. Not supported yet.
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WITH users_events AS (
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-- router select query
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WITH users_events_1 AS (
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SELECT
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*
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FROM
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users_table
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WHERE
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user_id = 1
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),
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-- real-time select query
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users_events_2_3 AS (
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SELECT
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*
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FROM
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users_table
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WHERE
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user_id = 2
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OR
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user_id = 3
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),
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-- router select query
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-- sub CTE is a real-time executor query but the top level is router select
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users_events_4 AS (
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WITH users_events_4_5 AS (
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SELECT
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*
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FROM
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users_table
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WHERE
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user_id = 4
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OR
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user_id = 5
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)
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SELECT
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*
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FROM
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users_events_4_5
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WHERE
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user_id = 4
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)
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-- merge all the results from CTEs
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SELECT
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*
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FROM
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users_events_1
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UNION
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SELECT
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*
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FROM
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users_events_2_3
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UNION
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SELECT
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*
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FROM
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users_events_4
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)
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SELECT
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*
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FROM
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users_events
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ORDER BY
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1, 2, 3, 4, 5, 6
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LIMIT
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20;
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-- access to uncle, use window function, apply aggregates, use group by, LIMIT/OFFSET
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WITH cte1 AS (
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WITH cte1_1 AS (
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WITH cte1_1_1 AS (
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SELECT user_id, time, value_2 FROM users_table
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),
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cte1_1_2 AS (
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SELECT
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user_id, count
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FROM (
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SELECT
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user_id,
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count(value_2) OVER (PARTITION BY user_id)
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FROM
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users_table
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GROUP BY 1, users_table.value_2
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)aa
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GROUP BY
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1,2
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ORDER BY
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1,2
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LIMIT
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4
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OFFSET
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2
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)
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SELECT cte1_1_1.user_id, cte1_1_1.time, cte1_1_2.count FROM cte1_1_1 join cte1_1_2 on cte1_1_1.user_id=cte1_1_2.user_id
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),
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cte1_2 AS (
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WITH cte1_2_1 AS (
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SELECT
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user_id, time, avg(value_1)::real as value_1, min(value_2) as value_2
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FROM
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users_table
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GROUP BY
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1, 2
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),
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cte1_2_2 AS (
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SELECT cte1_2_1.user_id, cte1_1.time, cte1_2_1.value_1, cte1_1.count FROM cte1_2_1 join cte1_1 on cte1_2_1.time=cte1_1.time and cte1_2_1.user_id=cte1_1.user_id
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)
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SELECT * FROM cte1_2_2
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)
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SELECT * FROM cte1_2
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),
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cte2 AS (
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WITH cte2_1 AS (
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WITH cte2_1_1 AS (
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SELECT * FROM cte1
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)
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SELECT user_id, time, value_1, min(count) FROM cte2_1_1 GROUP BY 1, 2, 3 ORDER BY 1,2,3
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)
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SELECT * FROM cte2_1 LIMIT 3 OFFSET 2
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)
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SELECT * FROM cte2;
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DROP SCHEMA with_nested CASCADE;
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