I'm searching to copy nodes of a hierarchical tree and to apply the changes onto a joined table. I found parts of the answer in other questions like Postgresql copy data within the tree table for the tree copy (in my case I only copy the children and not the root) and PostgreSQL - Insert data into multiple tables simultaneously to insert data in several table simultaneously, but I don't manage to mix them.
I would like to:
Generate the new nodes id from the fields table
Insert the new field ids in the data_versions table
Insert the new nodes in the fields table with the data_id from the data_versions table
Note: there is a circular reference between the fields and the data_versions tables.
See below the schema:
Here is a working query, but without the insert in the data_versions table. It is only a shallow copy (keeping the same data_id) while I would like a deep copy:
WITH created_data AS (
WITH RECURSIVE cte AS (
SELECT *, nextval('fields_id_seq') new_id FROM fields WHERE parent_id = :source_field_id
UNION ALL
SELECT fields.*, nextval('fields_id_seq') new_id FROM cte JOIN fields ON cte.id = fields.parent_id
)
SELECT C1.new_id, C1.name, C1.field_type, C1.data_id, C2.new_id new_parent_id
FROM cte C1 LEFT JOIN cte C2 ON C1.parent_id = C2.id
)
INSERT INTO fields (id, name, parent_id, field_type, data_id)
SELECT new_id, name, COALESCE(new_parent_id, :target_field_id), field_type, data_id FROM created_data
RETURNING id, name, parent_id, field_type, data_id;
And here is the draft query I'm working on for inserting data in the data_versions table resulting with WITH clause containing a data-modifying statement must be at the top level as an error:
WITH created_data AS (
WITH cloned_fields AS (
WITH RECURSIVE cte AS (
SELECT *, nextval('fields_id_seq') new_id FROM fields WHERE parent_id = :source_field_id
UNION ALL
SELECT fields.*, nextval('fields_id_seq') new_id FROM cte JOIN fields ON cte.id = fields.parent_id
)
SELECT C1.new_id, C1.name, C1.field_type, C1.data_id, C2.new_id new_parent_id
FROM cte C1 LEFT JOIN cte C2 ON C1.parent_id = C2.id
),
cloned_data AS (
INSERT INTO data_versions (value, author, field_id)
SELECT d.value, d.author, c.new_id
FROM cloned_fields c
INNER JOIN data_versions d ON c.data_id = d.id
RETURNING id data_id
)
SELECT cloned_fields.new_id, cloned_fields.name, cloned_fields.field_type, cloned_fields.new_parent_id, cloned_data.data_id
FROM cloned_fields
INNER JOIN cloned_data ON cloned_fields.data_id = cloned_data.id
)
INSERT INTO fields (id, name, parent_id, field_type, data_id)
SELECT new_id, name, COALESCE(new_parent_id, :target_field_id), field_type, data_id FROM created_data
RETURNING id, name, parent_id, field_type, data_id, value data;
If other people were encountering the same issue as me, I came up with this solution some months later. The trick was to move the data-modifying CTE at the top level as suggested by the error message. We can always access previously declared CTE's:
WITH new_fields_ids AS (
WITH RECURSIVE cte AS (
SELECT *, nextval('fields_id_seq') new_id FROM fields WHERE parent_id = :source_field_id
UNION ALL
SELECT fields.*, nextval('fields_id_seq') new_id FROM cte JOIN fields ON cte.id = fields.parent_id
)
SELECT C1.new_id, C1.name, C1.field_type, C1.data_id, C2.new_id new_parent_id
FROM cte C1 LEFT JOIN cte C2 ON C1.parent_id = C2.id
),
cloned_data AS (
INSERT INTO data_versions (value, author, field_id)
SELECT d.value, d.author, c.new_id
FROM new_fields_ids c
INNER JOIN data_versions d ON c.data_id = d.id
RETURNING id AS data_id, field_id, value
),
created_data AS (
SELECT new_fields_ids.new_id, new_fields_ids.name, new_fields_ids.field_type, new_fields_ids.new_parent_id, cloned_data.data_id
FROM new_fields_ids
INNER JOIN cloned_data ON new_fields_ids.new_id = cloned_data.field_id
),
cloned_fields AS (
INSERT INTO fields (id, name, parent_id, field_type, data_id)
SELECT new_id, name, COALESCE(new_parent_id, :target_field_id), field_type, data_id FROM created_data
RETURNING id, name, parent_id, field_type, data_id
)
SELECT f.id, f.name, f.parent_id, f.field_type, f.data_id, d.value AS data FROM cloned_fields f
INNER JOIN cloned_data d ON f.id = d.field_id;
I am learning sql (postgres) and id like to find values that do not exist.
I have a table, table 1 with ids and i want to find those ids that are not in table 4.
I have to join between 3 tables as table 1 holds id and table 4 contact_id (not the same number)
The tables 2,3 need to be joined as that connects the ids.
So how do i do that with “not exists”?
Select t1.id, table4.contact_id
From table1 t1
Join table2 using(id)
Join table3 using(id)
Join table4 using(contact_id)
Where not exists (
Select 1
From table4
Where table4.contact_id=t1.id
);
It returns no values, but should
No error msg…
I have thinking error i assume
Your query probably returns no values because you join table4 on contact_id and then you exclude in the WHERE clause the rows which come from this join.
To find values that don't exist, you can usually use LEFT JOIN or RIGHT JOIN or FULL OUTER JOIN and then filter the rows with NULL values in the WHERE clause.
Try this :
SELECT t1.id
FROM table1 t1
LEFT JOIN table2 t2 using(id)
LEFT JOIN table3 t3 using(id)
LEFT JOIN table4 t4 using(contact_id)
WHERE t4.contact_id IS NULL
I have two tables of records that I need to find all of the matches. The tables are based on different Primary Key identifiers, but the data points are exactly the same. I need a fast query that can show me records that are duplicated from the first table to the second. Here is an example of what I am trying to do:
DECLARE #Table1 TABLE (ID INT, Value INT)
DECLARE #Table2 TABLE (ID INT, Value INT)
INSERT INTO #Table1 VALUES (1, 500)
INSERT INTO #Table1 VALUES (2, 500)
INSERT INTO #Table2 VALUES (3, 500)
INSERT INTO #Table2 VALUES (4, 500)
SELECT MAX(x.T1ID)
,MAX(x.T2ID)
FROM (
SELECT T1ID = t1.ID
,T2ID = 0
,t1.Value
FROM #Table1 t1
UNION ALL
SELECT T1ID = 0
,T2ID = t2.ID
,t2.Value
FROM #Table2 t2
) x
GROUP BY x.Value
HAVING COUNT(*) >= 2
The problem with this code is that it returns record 2 in table 1 correlated to record 4 in table 2. I really need it to return record 1 in table 1 correlated to record 3 in table 2. I tried the following:
SELECT MIN(x.T1ID)
,MIN(x.T2ID)
FROM (
SELECT T1ID = t1.ID
,T2ID = 0
,t1.Value
FROM #Table1 t1
UNION ALL
SELECT T1ID = 0
,T2ID = t2.ID
,t2.Value
FROM #Table2 t2
) x
GROUP BY x.Value
HAVING COUNT(*) >= 2
This code does not work either. It returns 0,0.
Is there a way to return the MIN value greater than 0 for both tables?
Might answer my own question. This seems to work. Are there any reasons why I would not do this?
SELECT MIN(t1.ID)
,MIN(t2.ID)
FROM #Table1 t1
INNER JOIN #Table2 t2 ON t1.Value = t2.Value
GROUP BY t1.Value
If you want to see the records in table1 that have matches in table2 then
select *
from #Table1 T1
where exists (select * from #Table2 T2
where T1.ID=T2.ID
-- you would put the complete join clause that defines a match here
)
OK so I have a query I am trying to build.. I have 2 tables, table1 has a bunch of regular records as normal with a unique ID (auto increment) and table2 has records that include some of those ids from table1. I am trying to order by the highest records with that same ID in table1.. Heres what I've got:
SELECT * FROM table1
WHERE table1.status = 1
AND (SELECT COUNT(*) FROM table2 WHERE table2.tbl1_id = table1.id)
ORDER BY table1.id DESC
Thanks :)
SELECT table1.id
FROM table1
LEFT JOIN table2 ON table2.tbl1_id = table1.id
WHERE table1.status = 1
GROUP BY table1.id
ORDER BY COUNT(table2.tbl1_id) DESC
Try this:
SELECT a.*, b.cnt
FROM table1 a LEFT JOIN
(
SELECT tbl1_id, COUNT(*) cnt
FROM table2
GROUP BY tbl1_id
) b
ON a.id = b.tbl1_id
WHERE table1.status = 1
ORDER BY cnt DESC
I have a SQL like this:
Select tbl.id, tbl.name
From
(select table1.id, table1.name
from table1
inner join table2 on table1.id = table2.id
order by table2.priority
) tbl
group by table1.id
order by table1.name
What I'm trying to achieve is to first sort (order by table2.priority), and then get the record with table1.id, name with highest priority.
Note, MAX(table2.priority) doesn't work here, because table1 to table2 is one to many, and for one table1 record, table2 can have N records with the highest priority = 1, where another table1 record with highest priority = 3.
If you only need one record from the result, and they are in order such that the record you need is at the end (or beginning) of the sort, simply limit the results to one. i.e:
SELECT tbl.id, tbl.name
FROM (
SELECT table1.id, table1.name
FROM table1
INNER JOIN table2 ON table1.id = table2.id
ORDER BY table2.priority
) tbl
GROUP BY table1.id
ORDER BY table1.name
LIMIT 1;
Note that depending on the order, you could specify ASC or DESC to ensure the correct record is the one you retrieve.