Update with Where, Order by and Limit does not work - sql

Question

I am using SQLite 3.
When I input the following query
UPDATE MyTable Set Flag = 1 WHERE ID = 5 Order By OrderID DESC LIMIT 1;
I will always get an error:
near Order By, syntax error
I cannot figure out what is the problem with my query

Answer 1

To use LIMIT and ORDER BY in an UPDATE or DELETE statement, you have to do two things:
Build a custom version of the sqlite3.c amalgamation from source, configuring it with the --enable-update-limit option.
Compile that custom sqlite3.c into your project with SQLITE_ENABLE_UPDATE_DELETE_LIMIT defined to 1.

Answer 2

"Order By OrderID DESC LIMIT 1" is for selecting top one ordered result
so you should use it in select query.
you should do a subquery where you first get the id and then update it:
UPDATE MyTable
SET Flag = 1
WHERE (ID,OrderID) IN (SELECT ID,OrderID
FROM MyTable
WHERE ID = 5
ORDER BY OrderID DESC LIMIT 1);
Demo

Answer 3

You could use ROWID:
UPDATE MyTable
SET Flag = 1
WHERE ROWID IN (SELECT ROWID FROM MyTable WHERE ID = 5
ORDER BY OrderID DESC LIMIT 1);
db<>fiddle demo
or (ID,OrderID) tuple:
UPDATE MyTable
SET Flag = 1
WHERE (ID, ORDERID) IN (SELECT ID, ORDERID FROM MyTable WHERE ID = 5
ORDER BY OrderID DESC LIMIT 1);
db<>fiddle demo2
And if you need to do it in bulk for every ID(SQLite 3.25.0):
WITH cte AS (
SELECT *,ROW_NUMBER() OVER(PARTITION BY ID ORDER BY OrderID DESC) AS rn FROM tab
)
UPDATE tab
SET Flag = 1
WHERE (ID, OrderID) IN (
SELECT ID, OrderID
FROM cte
WHERE rn = 1
);

Answer 4

Order By statement will not work in update query.
You have to use alternate way
UPDATE MyTable Set Flag = 1 WHERE ID = 5
and OrderId = (select max(OrderId) from MyTable where Id = 5);
If you have used the query like above it will work.

Answer 5

Introduction
Below I'm presenting two solutions to solve the issue and perform a proper UPDATE. At the end of each solution there's a live example on sample data included.
First does not require you to input any id and works for the entire table by picking the latest orderid for each id and changing it's flag to 1
Second requires you to input an id and works only for updating one id on the run
I'd personally go with first solution, but I am not sure about your requirement, thus posting two possibilities.
First solution - update entire table
Explanation here, for code scroll down.
For this we will use Row Value construction (id, orderid) just like for the second solution.
It will find the latest row based on orderid and update only that row for given (id, orderid) pair. More on that is included in Explanation of second solution.
We will also need to simulate row_number function to assign each row ranking numbers, to find out which row has the latest orderid for every id and mark then as 1 to be able to pull only those for update. This will allow us to update multiple rows for different ids in one statement. SQLite will have this functionality built in version 3.2.5 but for now, we will work with a subquery.
To generate row numbers we will use this:
select
*,
(select count(*) from mytable m1 where m1.id = m2.id and m1.orderid >= m2.orderid) as rn
from mytable m2
Then we just need to filter the output on rn = 1 and we have what we need.
That said, the whole UPDATE statement will look like:
Code
update mytable
set flag = 1
where (id,orderid) in (
select id, orderid
from (
select *, (select count(*) from mytable m1 where m1.id = m2.id and m1.orderid >= m2.orderid) as rn
from mytable m2
) m
where
m.rn = 1
and m.id = mytable.id
);
Live DEMO
Here's db fiddle to see this solution live on sample data.
Second solution - update only one ID
If you know your ID to be updated and want to run UPDATE statement for only one id, then this will work:
Code
update mytable
set flag = 1
where (id,orderid) in (
select id, orderid
from mytable
where id = 5
order by orderid desc
limit 1
);
Explanation
(id, orderid) is a construction called Row Value for which SQLite compares scalar values from left to right.
Example taken from documentation:
SELECT (1,2,3) = (1,2,3) -- outputs: 1
Live DEMO
Here's db fiddle to see this solution live on sample data.

Answer 6

SQL
UPDATE MyTable
SET Flag = 1
WHERE ID = 5
AND OrderID IN (SELECT OrderID
FROM MyTable
WHERE ID = 5
ORDER BY OrderID DESC
LIMIT 1);
Demo
SQLFiddle demo: http://sqlfiddle.com/#!5/6d596/2