I've go this request in SQL for a migration:
UPDATE table1
SET table1.value = table2.value
FROM table1
INNER JOIN table2
ON table2.othervalue2 = table1.key
WHERE table2.othervalue3 is NULL
Works well.
But not with Oracle. I know it isn't impossible to make join in a update with oracle, so I use this:
UPDATE table1 SET table1.value = (SELECT table2.value
FROM table2
WHERE table2.othervalue2 = table1.key
AND table2.othervalue3 is NULL)
WHERE EXISTS (SELECT table2.value
FROM table2
WHERE table2.othervalue2 = table1.key
AND table2.othervalue3 is NULL)
but I have an ORA-01427: Subquery returns more than one row.
Thanks
i would say you have inconsistent data. From the Errors you get i would say you have duplicates in the query specified.
SELECT table2.value
FROM table2
WHERE table2.othervalue2 = table1.key
AND table2.othervalue3 is NULL
you might wanne check it.or you need to have the data better specified you want to select for Update/Merge.
Related
In Microsoft SQL Server,
if the inner select doesn't have a matching criteria, then I need to update Field1 with blank instead of null.
UPDATE Table1
SET Field1=(
SELECT Field2
FROM Table2
WHERE Table2.Field3 = Table1.Field4
)
Please try like this -
UPDATE a
SET a.Field1 = ISNULL(b.Field2,'')
FROM Table1 a
LEFT JOIN Table2 b ON b.Field3 = a.Field4
You can reference another table using SQL Server's UPDATE ... FROM ... syntax:
UPDATE t1
SET field1 = COALESCE(t2.field2, '')
FROM Table1 t1
LEFT JOIN
Table2 t2
ON t2.Field3 = t1.Field4
The COALESCE() function returns the first non-null expression in a list. You can keep most of your original query, by using COALESCE() to replace any NULL from that query with an empty string.
UPDATE Table1
SET Field1=COALESCE((
SELECT Field2
FROM Table2
WHERE Table2.Field3 = Table1.Field4
), '')
Try this
UPDATE T1
SET T1.Field1=isnull(T2.Field2,'')
from Table1 T1 left join Table2 T2
ON T2.Field3 = T1.Field4
I have three tables and I have to write one query to update table 1 row from table 3 and the only matching columns I have is in table 2.
Table 1 which has incorrect data:
Table 3 has the correct data:
I did try to write a query and execute it but it gives me an error saying there are too many rows too select which is true I do have many rows to correct but it still wouldn't correct. What do you think I should do. This is my query so far.
UPDATE Table1
SET Table1.Number = (SELECT Table3.Number
FROM Table2
FULL OUTER JOIN Table1 ON Table1.ID = Table2.ID
FULL OUTER JOIN Table3 ON Table3.Signin = Table2.Signin
WHERE (Table2.ID = Table1.ID)
AND (Table1.Number = 'xxx'))
WHERE (Tale1.Number = 'xxx')
In Where clause of JOIN query need to modify as multiple records are generating by inappropriate condition.Try to use Table3 components instead of using Table1 in joining query where clause.
UPDATE Table1
SET Table1.NUMBER = (SELECT table3.NUMBER FROM Table1 FULL OUTER JOIN Table2
ON Table1.ID = Table2.ID
FULL OUTER JOIN Table3
ON Table2.SIGNIN = Table3.SIGNIN
WHERE Table3.SIGNIN = 100) // This is the point where you need to modify your code
WHERE Table1.ID = 1;
ONLINE DEMO HERE
It actually worked after I removed this line from my query.
FULL OUTER JOIN Table1 ON table1.ID = Table2.ID
Thanks for the help.
You are fairly close. When doing the update though unless you are wanting to clear value for t1.number when a record is not matched in t3, you will want to use INNER JOIN. FULL OUTER JOIN would mean you are trying to update rows in t1 that don't exist but a LEFT JOIN you would update t1.number to NULL if a record in t3 doesn't exist.
UPDATE t1
SET t1.Number = t3.Number
FROM
Table1 t1
INNER JOIN Table2 t2
ON t1.Id = t2.Id
INNER JOIN Table3 t3
ON t2.Signin = t.3.Signin
WHERE
t1.number <> t3.number
--Or if you have nulls something like
--ISNULL(t1.number,'xxx') <> ISNULL(t3.number,'xxx')
-- if you only want to update when t1.number = 'xxx' then
--t1.number = 'xxx'
t1,t2,t3 are table aliases that I created by adding the alias after table name. By using join syntax rather than a sub select you simplify your were conditions. In sql-sever if more than 1 record in t2 & t3 match it will select one row randomly in the case of a one to many relationship. If you want a specific record when not one to one relation you can use window functions and common table expressions (cte) to limit t3 to the exact record you want to use.
This is a common SQL query for me:
update table1 set col1 = (select col1 from table2 where table1.ID = table2.ID)
where exists (select 1 from table2 where table1.ID = table2.ID)
Is there any way to avoid having two nearly identical subqueries? This query is an obvious simplification but performance suffers and query is needlessly messy to read.
Unfortunately Informix don't support the FROM clause at UPDATE statement.
The way to workaround and you will get better results (performance) is change the UPDATE to MERGE statement.
This will work only if your database is version 11.50 or above
MERGE INTO table1 as t1
USING table2 as t2
ON t1.ID = t2.ID
WHEN MATCHED THEN UPDATE set (t1.col1, t1.col2) = (t2.col1, t2.col2);
Check IBM Informix manual for more information
Update with inner join can be used to avoid subqueries
something like this:
update t1
set col1 = t2.col1
from table1 t1
inner join table2 t2
on t1.ID = t2.ID
try this:
update table1 set col1 = (select col1 as newcol from table2 where table1.ID = table2.ID)
where exists (newcol)
I'm trying to execute a query that looks similar to this:
SELECT <columns> FROM table1
INNER JOIN table2 ON table1.id = table2.table1_id
INNER JOIN table3 ON table1.id = table3.table1_id
WHERE table3.column1 != 'foo' AND <other_conditions>
LIMIT 1;
The thing is--I want the query to return a result regardless of whether the record in table3 exists or not. That is--if the record in table3 is present, I want to check whether that record has a certain column value. If the record in table3 doesn't exist, I want the query to assume that the condition is TRUE.
Any pointers?
You use a left join on the table. If no corresponding record exists, the value from the table will be null, so you can use coalesce to get a value that you can compare to the string:
SELECT <columns> FROM table1
INNER JOIN table2 ON table1.id = table2.table1_id
LEFT JOIN table3 ON table1.id = table3.table1_id
WHERE COALESCE(table3.column1, '') != 'foo' AND <other_conditions>
LIMIT 1
You've come to a point where you noticed that there is a difference between WHERE conditions and JOIN conditions.
SELECT
<columns>
FROM
table1
INNER JOIN table2 ON table2.table1_id = table1.id
LEFT JOIN table3 ON table3.table1_id = table1.id AND table3.column1 <> 'foo'
WHERE
<other_conditions>
LIMIT 1;
You need to use an outer join to include table3 instead of an inner join.
I know its almost there, but base is telling me it can't find a column called table1.id when I know its there!
UPDATE table2 SET col1 = (SELECT field1 FROM table1 WHERE table2.id = table1.id) WHERE table1.id = table2.id
UPDATE table2 SET col1 = (SELECT field1 FROM table1 WHERE table2.id = table1.id)
table1 is unknown in the outer SQL.
What I get from your query, this will work
UPDATE table2 SET col1 = t1.field1
FROM table2 t2 INNER JOIN table1 t1 ON t2.id = t1.id
Instead of using a WHERE clause, try using an INNER JOIN clause. It is indeed late so forgive me for my code haha
UPDATE table2
SET col1 = (SELECT field1
FROM table1
WHERE table2.id = table1.id)
INNER JOIN table1
ON table2.id = table1.id
Option 1: No need to have outer WHERE clause.
Option 2: Do not use inner query unneccesarily. Use Inner Join instead