Update values in one table with values in another table - sql

I have table1 and table2. They have the same columns and the column ID is the one that i can use to connect the tables.
How can i run foreach statment that will update row Name in table1 with the value for column Name in table2?
I need this so i can fix the column Name in Table1 because it is incorect , and the good values for it are in table2
I tried using a single update statement but it takes forever to execute because both tables are with over 600 000 rows
update
table1 t1
set
(
t1.name
) = (
select
t2.name
from
table2 t2
where
t2.id = t1.id
and
rownum = 1
)
where exists (
select
null
from
table2 t2
where
t2.id = t1.id
);

For this query:
update table1 t1
set t1.name = (select t2.name from table2 t2 where t2.id = t1.id and rownum = 1)
where exists (select 1
from table2 t2
where t2.id = t1.id
);
You want an index on table2(id, name).

A simple inner join should work this.
UPDATE T1
SET T1.NAME = T2.NAME
FROM MyTable T1
INNER JOIN MyOtherTable T2
ON T1.ID = T2.ID

Related

SAS SQL inner join two columns able to match one column

How can I do something like select * from T1 inner join T2 on (T1.ID=T2.ID OR T1.ID2=T2.ID)
When I execute this code, it seems to fall in a infinity loop so I guess I'm wrong.
In other words, how can I match one of two columns from T1 to one column from T2
T1
ID ID2
1 10
2 20
T2
ID value
1 dummy10
20 dummy20
Result
ID ID2 value
1 10 dummy10
2 20 dummy20
Try to do like this:
select *
from T1, T2
where T1.ID = T2.ID or T1.ID2 = T2.ID
you can use 2 select statements with union, like this:
select
t1.ID,
t1.ID2,
t2.value
from Table1 as t1
inner join Table2 as t2 on t1.ID = t2.ID
UNION
select
t1.ID,
t1.ID2,
t2.value
from Table1 as t1
inner join Table2 as t2 on t1.ID2 = t2.ID
/* this will exclude values selected by other statement */
where t1.ID2 not in (select ID2 from Table1 inner join Table2 on Table1.ID = Table2.ID)
The only issue I can see with the code you provide is that you have not specified from which table you want the common column ID to be selected:
proc sql;
select
t1.*
,t2.value
from t1
inner join t2
on t1.id = t2.id or t1.id2 = t2.id;
quit;
Otherwise, your code should work. Perhaps the size of the data being joined is the problem?

How to update multiple columns in the oracle SQL on ATP fusion DB

I am trying to use the below query, its everytime saying cannot insert null for the second column.
UPDATE TABLE1
SET (COL1,COL2,COL3) = (SELECT COL1,COL2,COL3
FROM TABLE2
WHERE t1.id = t2.id);
Try this:
UPDATE TABLE1 SET (COL1,COL2,COL3) =
(SELECT COL1,NVL(COL2,0),COL3 FROM TABLE1 T1, TABLE2 T2 where t1.id = t2.id)
WHERE <YOUR WHERE CONDITION>
I would use a MERGE:
MERGE INTO TABLE1 t1
USING (SELECT id, COL1,COL2,COL3
FROM TABLE2) t2
ON (t1.id = t2.id)
WHEN MATCHED THEN UPDATE SET t1.COL1 = t2.COL1
, t1.COL2 = t2.COL2
, t1.COL3 = t2.COL3;
There are rows in table1 where not corresponding row exists in table2 thus the sub-query returns nothing which means the UPDATE statement will take that as null for all three columns.
You have to add a WHERE clause that only updates rows in table1 that do have a matching row in table2
UPDATE TABLE1
SET (COL1,COL2,COL3) = (SELECT COL1,COL2,COL3
FROM TABLE2 t2
WHERE table1.id = t2.id)
where exist (select *
from table2 t2
where table1.id = t2.id);

How to add a column in a table from another table having common id column in both the tables in SQL Server?

I am trying to update a table1 with a Column2 from table2 where id should match while inserting the Column2 values from table2 in table1 for SQL Server.
I tried with the below 2 sets of code, but it is not working.
Can anyone help me out with this?
alter table table1
add Column2 varchar(20)
insert into table1
Select t2.Column2
from table1 as t1
inner join table2 as t2
on t1.id = t2.id
And, below also:
Update table1
Set Column2 = (Select t2.Column2
from table1 as t1
inner join table2 as t2
on t1.id = t2.id)
Update t1
Set Column2 = t2.Column2
from table1 as t1
inner join table2 as t2
on t1.id = t2.id

How to Update column values of t1 from Table t2?

I want to select t2 column values (Name) and update with t1 column values (Name) without where clause. what will be the query?
I am executing below code:
update t1 set t1.name=t2.name from t2 where t1.id=t2.id
but I want to perform it without WHERE clause.
Join both tables on id:
UPDATE t1 SET t1.Name = t2.Name
FROM TableName1 t1
INNER JOIN TableName2 t2 ON t1.Id = t2.Id
We use MERGE nowadays:
MERGE t1 USING t2 ON t1.id = t2.id
WHEN MATCHED THEN
UPDATE SET name = t2.name;
just do it
UPDATE t1
SET t1.name=t2.name
FROM table1 t1 INNER JOIN table2 t2 ON t1.id=t2.id

SQL: select from t1 all rows for which there's no corresponding in t2

Let's say I have a table t1 with only one column: id, and I have a table t2 with two columns: id and Memo. I need to select those id from t1, for which there is NO row in t2 that satisfies both of the following two conditions t1.id = t2.id and t2.Memo = 'myText'. How can I do that? I have tried using join, but that selects row that do satisfy some conditions, whereas I need the opposite.
SELECT *
FROM t1
WHERE NOT EXISTS (SELECT 1
FROM t2
WHERE t2.id = t1.id
AND t2.Memo = 'myText')
One way to do it is using LEFT JOIN:
select id
from t1
left join t2
on t1.id = t2.id and t2.Memo = 'myText'
where t2.id is null
I'm not good in understanding your question:
You mean those t1.id EXISTS in t2 BUT the corresponding t2.Memo <> 'myText'?
SELECT t1.id FROM t1 JOIN t2
ON t1.id = t2.id
HAVING t1.id NOT IN (SELECT id FROM t2 WHERE Memo = 'myText');
Or all t1.id either NOT EXISTS in t2 or EXISTS but Memo <> 'myText'?
SELECT id FROM t1 WHERE id NOT IN (SELECT id FROM t2 WHERE Memo = 'myText');