MySQL-复杂的INNER JOIN和CONCAT查询错误

Question

I am getting an error ER_BAD_FIELD_ERROR: Unknown column 'year_fk' in 'field list' on this query:

    SELECT CONCAT('program:', program_pk) AS global_id,
       program_name AS name,
       NULL AS parent_global_id
FROM program
UNION ALL
SELECT CONCAT('year:', year_pk) AS global_id,
       year_name AS name,
       CONCAT('program:', program_fk) AS parent_global_id
FROM year 
UNION ALL
SELECT 
       CONCAT('year:', year_fk, ',unit:', unit_name) AS global_id,
       unit_name AS name,
       CONCAT('year:', year_fk) AS parent_global_id
FROM unit
UNION ALL
SELECT 
       CONCAT('year:', year_fk, ',unit:', unit_name, ',rotation_discipline_block:', rotation_discipline_block_name) AS global_id,
       rotation_discipline_block_name AS name,
       CONCAT('year:', year_fk, ',unit:', unit_name) AS parent_global_id
FROM rotation_discipline_block rdb
INNER JOIN unit u ON u.unit_pk = rdb.unit_fk
UNION ALL
SELECT 
       CONCAT('year:', year_fk, ',unit:', unit_name, ',rotation_discipline_block:', rotation_discipline_block_name, ',week:', week_name) AS global_id,
       week_name AS name,
       CONCAT('year:', year_fk, ',unit:', unit_name, ',rotation_discipline_block:', rotation_discipline_block_name) AS parent_global_id
FROM week wk
UNION ALL
SELECT 
       CONCAT('year:', year_fk, ',unit:', unit_name, ',rotation_discipline_block:', rotation_discipline_block_name, ',learning_event:', learning_event_name) AS global_id,
       learning_event_name AS name,
       CONCAT('year:', year_fk, ',unit:', unit_name, ',rotation_discipline_block:', rotation_discipline_block_name) AS parent_global_id
FROM learning_event le
INNER JOIN week wk ON wk.week_pk = le.week_fk
INNER JOIN rotation_discipline_block rdb ON rdb.rotation_discipline_block_pk = wk.rotation_discipline_block_fk
INNER JOIN unit u ON u.unit_pk = rdb.unit_fk
INNER JOIN year y ON u.year_fk = y.year_pk
ORDER BY name

Not sure which part of the query that contains year_fk though...

See db-fiddle

Answer 1

OK, solved it myself:

SELECT CONCAT('program:', program_pk) AS global_id,
       program_name AS name,
       NULL AS parent_global_id
FROM program
UNION ALL
SELECT CONCAT('year:', year_pk) AS global_id,
       year_name AS name,
       CONCAT('program:', program_fk) AS parent_global_id
FROM year 
UNION ALL
SELECT 
       CONCAT('year:', year_fk, ',unit:', unit_name) AS global_id,
       unit_name AS name,
       CONCAT('year:', year_fk) AS parent_global_id
FROM unit
UNION ALL
SELECT 
       CONCAT('year:', year_fk, ',unit:', unit_name, ',rotation_discipline_block:', rotation_discipline_block_name) AS global_id,
       rotation_discipline_block_name AS name,
       CONCAT('year:', year_fk, ',unit:', unit_name) AS parent_global_id
FROM rotation_discipline_block rdb
INNER JOIN unit u ON u.unit_pk = rdb.unit_fk
UNION ALL
SELECT 
       CONCAT('year:', year_fk, ',unit:', unit_name, ',rotation_discipline_block:', rotation_discipline_block_name, ',week:', week_name) AS global_id,
       week_name AS name,
       CONCAT('year:', year_fk, ',unit:', unit_name, ',rotation_discipline_block:', rotation_discipline_block_name) AS parent_global_id
FROM week wk
INNER JOIN rotation_discipline_block rdb ON rdb.rotation_discipline_block_pk = wk.rotation_discipline_block_fk
INNER JOIN unit u ON u.unit_pk = rdb.unit_fk
INNER JOIN year y ON u.year_fk = y.year_pk
UNION ALL
SELECT 
       CONCAT('year:', year_fk, ',unit:', unit_name, ',rotation_discipline_block:', rotation_discipline_block_name, ',week:', week_name, ',learning_event:', learning_event_name) AS global_id,
       learning_event_name AS name,
       CONCAT('year:', year_fk, ',unit:', unit_name, ',rotation_discipline_block:', rotation_discipline_block_name, ',week:', week_name) AS parent_global_id
FROM learning_event le
INNER JOIN week wk ON wk.week_pk = le.week_fk
INNER JOIN rotation_discipline_block rdb ON rdb.rotation_discipline_block_pk = wk.rotation_discipline_block_fk
INNER JOIN unit u ON u.unit_pk = rdb.unit_fk
INNER JOIN year y ON u.year_fk = y.year_pk
ORDER BY name

db-fiddle