I want to insert into a first table, then update a second table with the returned (DB generated) UUID of the inserted row before finally returning the result of the insert.
The insert query looks like this:
INSERT INTO public.organisations ("name")
VALUES('StackOverflow')
RETURNING *
This will return a row with name, data and id. Data is an empty JSON and can be ignored, id is the UUID used below.
The update query looks like this, with <orgId> indicating the UUID generated and returned by the above insert and <userId> indicating a value passed in from code:
UPDATE public.users
SET id_organisation = <orgID>, last_modified_by = <userID>
WHERE id = <userID>;
Both of these queries work but I do not know how to string them together and return the output of the first query.
Is it possible to do this or would I be better just running two queries?
Use CTEs:
with i as (
INSERT INTO public.organisations ("name")
VALUES('StackOverflow')
RETURNING *
)
UPDATE public.users
SET id_organisation = (SELECT i.id FROM i LIMIT 1), last_modified_by = <userID>
WHERE id=<userID>;
Note that this uses a subquery with LIMIT -- this guarantees that at most one row is returned.
Here is a db<>fiddle illustrating that the syntax works.
Related
I am looking to insert or update values in an SQLite database (version > 3.35) avoiding multiple queries. upsert along with returning seems promising :
CREATE TABLE phonebook2(
name TEXT PRIMARY KEY,
phonenumber TEXT,
validDate DATE
);
INSERT INTO phonebook2(name,phonenumber,validDate)
VALUES('Alice','704-555-1212','2018-05-08')
ON CONFLICT(name) DO UPDATE SET
phonenumber=excluded.phonenumber,
validDate=excluded.validDate
WHERE excluded.validDate>phonebook2.validDate RETURNING name;
This helps me track names corresponding to inserted/modified rows. How to find rows where phonebook2 values conflict with values upserted in above statement, but no insert or update happened due to where clause?
The RETURNING clause can't be used to get non-affected rows.
What you can do is execute a SELECT statement before the UPSERT:
WITH cte(name, phonenumber, validDate) AS (VALUES
('Alice', '704-555-1212', '2018-05-08'),
('Bob','804-555-1212', '2018-05-09')
)
SELECT *
FROM phonebook2 p
WHERE EXISTS (
SELECT *
FROM cte c
WHERE c.name = p.name AND c.validDate <= p.validDate
);
In the CTE you may include as many tuples as you want
I would like to update rows with values chosen randomly from a set of possible values.
Ideally I would be able to provide this values at runtime, using JdbcTemplate from Java application.
Example:
In a table, column "name" can contain any name. The goal is to run through the table and change all names to equal to either "Bob" or "Alice".
I know that this can be done by creating a sql function. I tested it and it was fine but I wonder if it is possible to just use simple query?
This will not work, seems that the value is computed once, and applied to all rows:
UPDATE test.table
SET first_name =
(SELECT a.name
FROM
(SELECT a.name, RAND() idx
FROM (VALUES('Alice'), ('Bob')) AS a(name) ORDER BY idx FETCH FIRST 1 ROW ONLY) as a)
;
I tried using MERGE INTO, but it won't even run (possible_names is not found in SET query). I am yet to figure out why:
MERGE INTO test.table
USING
(SELECT
names.fname
FROM
(VALUES('Alice'), ('Bob'), ('Rob')) AS names(fname)) AS possible_names
ON ( test.table.first_name IS NOT NULL )
WHEN MATCHED THEN
UPDATE SET
-- select random name
first_name = (SELECT fname FROM possible_names ORDER BY idx FETCH FIRST 1 ROW ONLY)
;
EDIT: If possible, I would like to only focus on fields being updated and not depend on knowing primary keys and such.
Db2 seems to be optimizing away the subselect that returns your supposedly random name, materializing it only once, hence all rows in the target table receive the same value.
To force subselect execution for each row you need to somehow correlate it to the table being updated, for example:
UPDATE test.table
SET first_name =
(SELECT a.name
FROM (VALUES('Alice'), ('Bob')) AS a(name)
ORDER BY RAND(ASCII(SUBSTR(first_name, 1, 1)))
FETCH FIRST 1 ROW ONLY)
or may be even
UPDATE test.table
SET first_name =
(SELECT a.name
FROM (VALUES('Alice'), ('Bob')) AS a(name)
ORDER BY first_name, RAND()
FETCH FIRST 1 ROW ONLY)
Now that the result of subselect seems to depend on the value of the corresponding row in the target table, there's no choice but to execute it for each row.
If your table has a primary key, this would work. I've assumed the PK is column id.
UPDATE test.table t
SET first_name =
( SELECT name from
( SELECT *, ROW_NUMBER() OVER(PARTITION BY id ORDER BY R) AS RN FROM
( SELECT *, RAND() R
FROM test.table, TABLE(VALUES('Alice'), ('Bob')) AS d(name)
)
)
AS u
WHERE t.id = u.id and rn = 1
)
;
There might be a nicer/more efficient solution, but I'll leave that to others.
FYI I used the following DDL and data to test the above.
create table test.table(id int not null primary key, first_name varchar(32));
insert into test.table values (1,'Flo'),(2,'Fred'),(3,'Sue'),(4,'John'),(5,'Jim');
I am trying to select the row in a table where the id = user and once I have that row I want to insert into the docId column the value docId. To do this I have tried this:
INSERT INTO (SELECT * FROM users WHERE (id='"+user+"')); (docId) VALUES ('"+docId+"')
but this does not work
I think you want:
update users
set docId = ?
where id = ?
Do not munge the query string with parameter values. These only cause unexpected syntax errors and make the code vulnerable to SQL injection. Learn to use parameters.
Try INSERT INTO TableNmae(SELECT * FROM users WHERE (id='value') and (docId) = ('value1'))
I m struggling to update one column for a table with a sub query. I have a table where currently one of the values is null.
Currently I have:
UPDATE DW1_PURCHASES SET DW1_PURCHASES.TOTAL_AMT =
(
SELECT DW1_PURCHASES.QUANTITY * DW1_PRODUCTS.PRICE
FROM DW1_PURCHASES, DW1_PRODUCTS
WHERE DW1_PURCHASES.PRODUCT_ID = DW1_PRODUCTS.PRODUCT_ID
)
Although subquery returns data which I need to insert I get a error of single row subquery returns multiple rows.How do I basically shift subquery result to the table?
Thanks.
You don't have to JOINthe update table inside the sub-query. Just correlate the sub-query with update table
UPDATE DW1_PURCHASES
SET DW1_PURCHASES.TOTAL_AMT =
(
SELECT DW1_PURCHASES.QUANTITY * DW1_PRODUCTS.PRICE
FROM DW1_PRODUCTS
WHERE DW1_PURCHASES.PRODUCT_ID = DW1_PRODUCTS.PRODUCT_ID
)
Note : If your DW1_PRODUCTS table has duplicated PRODUCT_ID then even now there is a possibility to get the same error
Is there any way to do some kind of "WITH...UPDATE" action on SQL?
For example:
WITH changes AS
(...)
UPDATE table
SET id = changes.target
FROM table INNER JOIN changes ON table.id = changes.base
WHERE table.id = changes.base;
Some context information: What I'm trying to do is to generate a base/target list from a table and then use it to change values in another table (changing values equal to base into target)
Thanks!
You can use merge, with the equivalent of your with clause as the using clause, but because you're updating the field you're joining on you need to do a bit more work; this:
merge into t42
using (
select 1 as base, 10 as target
from dual
) changes
on (t42.id = changes.base)
when matched then
update set t42.id = changes.target;
.. gives error:
ORA-38104: Columns referenced in the ON Clause cannot be updated: "T42"."ID"
Of course, it depends a bit what you're doing in the CTE, but as long as you can join to your table withint that to get the rowid you can use that for the on clause instead:
merge into t42
using (
select t42.id as base, t42.id * 10 as target, t42.rowid as r_id
from t42
where id in (1, 2)
) changes
on (t42.rowid = changes.r_id)
when matched then
update set t42.id = changes.target;
If I create my t42 table with an id column and have rows with values 1, 2 and 3, this will update the first two to 10 and 20, and leave the third one alone.
SQL Fiddle demo.
It doesn't have to be rowid, it can be a real column if it uniquely identifies the row; normally that would be an id, which would normally never change (as a primary key), you just can't use it and update it at the same time.