Combining Update Statement with Join - sql

I'm having a problem. I need to update a table using plsql, but the condition in the where clause will depend upon conditions in a different table. For example
UPDATE table1
set column1 = ...
where table2.column = ...
This isn't what I have. However, I do need to know how to properly do this.

Here's how you use a JOIN in an UPDATE query:
UPDATE table1 AS t1
JOIN table2 AS t2 ON t1.somecol = t2.someothercol
SET t1.column1 = ...
WHERE t2.column = ...

You can write an update command as follows:
UPDATE employees e SET taxable = 'Y'
WHERE EXISTS (SELECT 1 FROM SALARIES s
WHERE s.employee_id = e.employee_id
AND s.salary > LOWER_LIMIT)

Related

update with join in oracle sql

I want to update a column of a table1 but I should update only records where conditions are true in another table
something like this, but I don't know how to implement this purpose in Oracle SQL
update table1
join table2 on table1.msg_id = table2.id
set table1.index = table1.index-1
where table1.index > 10 and table2.type = 'myType'
I would write this as an exists subquery in any database:
update table1 t1
set index = t1.index - 1
where table1.index > 10 and
exists (select 1
from table2
where t2.id = t1.msg_id and
t2.type = 'myType'
);
The join sort of implies that you are going to use data from table2 in the update of table1. Instead, you simply want to change a value in a row when a particular condition is met.
Oracle does not support this syntax (sigh).
For your use case, you could use a not exists condition with a correlated subquery instead:
update table1
set table1.index = table1.index - 1
where
table1.index > 10
and exists (
select 1 from table2 where table1.msg_id = table2.id and table2.type = 'mytype'
)
Note: make your live easier, do not use index for a column name. This is a reserved work in pretty much all RDBMS.

oracle-sql UPDATE if conditions are true in multiple tables

I have got a problem with an update statement in sql. I want to update param1 in table1 if the conditions are true (shown in my example).
Currently I am trying this:
update table1
set table1.param1 = 1
from (select * table1, table2
where table1.param2=table2.paramA
and table2.paramB='123456'
and table1.param3='XXX123');
You can try this.
update (select *
from table1 join table2
on table1.param2=table2.paramA
where table2.paramB='123456'
and table1.param3='XXX123') t
set t.param1 = 1
You don't need to do join in subquery. You can do the join and update in one go. Please try below query for your update.
update table1 join table2 on table1.param2=table2.paramA
set table1.param1 = 1
where table2.paramB='123456'
and table1.param3='XXX123';

SQL command to compare results is not working [duplicate]

I want to update a column in a table making a join on other table e.g.:
UPDATE table1 a
INNER JOIN table2 b ON a.commonfield = b.[common field]
SET a.CalculatedColumn= b.[Calculated Column]
WHERE
b.[common field]= a.commonfield
AND a.BatchNO = '110'
But it is complaining :
Msg 170, Level 15, State 1, Line 2
Line 2: Incorrect syntax near 'a'.
What is wrong here?
You don't quite have SQL Server's proprietary UPDATE FROM syntax down. Also not sure why you needed to join on the CommonField and also filter on it afterward. Try this:
UPDATE t1
SET t1.CalculatedColumn = t2.[Calculated Column]
FROM dbo.Table1 AS t1
INNER JOIN dbo.Table2 AS t2
ON t1.CommonField = t2.[Common Field]
WHERE t1.BatchNo = '110';
If you're doing something silly - like constantly trying to set the value of one column to the aggregate of another column (which violates the principle of avoiding storing redundant data), you can use a CTE (common table expression) - see here and here for more details:
;WITH t2 AS
(
SELECT [key], CalculatedColumn = SUM(some_column)
FROM dbo.table2
GROUP BY [key]
)
UPDATE t1
SET t1.CalculatedColumn = t2.CalculatedColumn
FROM dbo.table1 AS t1
INNER JOIN t2
ON t1.[key] = t2.[key];
The reason this is silly, is that you're going to have to re-run this entire update every single time any row in table2 changes. A SUM is something you can always calculate at runtime and, in doing so, never have to worry that the result is stale.
Try it like this:
UPDATE a
SET a.CalculatedColumn= b.[Calculated Column]
FROM table1 a INNER JOIN table2 b ON a.commonfield = b.[common field]
WHERE a.BatchNO = '110'
Answer given above by Aaron is perfect:
UPDATE a
SET a.CalculatedColumn = b.[Calculated Column]
FROM Table1 AS a
INNER JOIN Table2 AS b
ON a.CommonField = b.[Common Field]
WHERE a.BatchNo = '110';
Just want to add why this problem occurs in SQL Server when we try to use alias of a table while updating that table, below mention syntax will always give error:
update tableName t
set t.name = 'books new'
where t.id = 1
case can be any if you are updating a single table or updating while using join.
Although above query will work fine in PL/SQL but not in SQL Server.
Correct way to update a table while using table alias in SQL Server is:
update t
set t.name = 'books new'
from tableName t
where t.id = 1
Hope it will help everybody why error came here.
MERGE table1 T
USING table2 S
ON T.CommonField = S."Common Field"
AND T.BatchNo = '110'
WHEN MATCHED THEN
UPDATE
SET CalculatedColumn = S."Calculated Column";
UPDATE mytable
SET myfield = CASE other_field
WHEN 1 THEN 'value'
WHEN 2 THEN 'value'
WHEN 3 THEN 'value'
END
From mytable
Join otherTable on otherTable.id = mytable.id
Where othertable.somecolumn = '1234'
More alternatives here.
Seems like SQL Server 2012 can handle the old update syntax of Teradata too:
UPDATE a
SET a.CalculatedColumn= b.[Calculated Column]
FROM table1 a, table2 b
WHERE
b.[common field]= a.commonfield
AND a.BatchNO = '110'
If I remember correctly, 2008R2 was giving error when I tried similar query.
I find it useful to turn an UPDATE into a SELECT to get the rows I want to update as a test before updating. If I can select the exact rows I want, I can update just those rows I want to update.
DECLARE #expense_report_id AS INT
SET #expense_report_id = 1027
--UPDATE expense_report_detail_distribution
--SET service_bill_id = 9
SELECT *
FROM expense_report_detail_distribution erdd
INNER JOIN expense_report_detail erd
INNER JOIN expense_report er
ON er.expense_report_id = erd.expense_report_id
ON erdd.expense_report_detail_id = erd.expense_report_detail_id
WHERE er.expense_report_id = #expense_report_id
Another approach would be to use MERGE
;WITH cteTable1(CalculatedColumn, CommonField)
AS
(
select CalculatedColumn, CommonField from Table1 Where BatchNo = '110'
)
MERGE cteTable1 AS target
USING (select "Calculated Column", "Common Field" FROM dbo.Table2) AS source ("Calculated Column", "Common Field")
ON (target.CommonField = source."Common Field")
WHEN MATCHED THEN
UPDATE SET target.CalculatedColumn = source."Calculated Column";
-Merge is part of the SQL Standard
-Also I'm pretty sure inner join updates are non deterministic..
Similar question here where the answer talks about that
http://ask.sqlservercentral.com/questions/19089/updating-two-tables-using-single-query.html
I think, this is what you are looking for.
UPDATE
Table1
SET
Table1.columeName =T1.columeName * T2.columeName
FROM
Table1 T1
INNER JOIN Table2 T2
ON T1.columeName = T2.columeName;
I had the same issue.. and you don't need to add a physical column.. cuz now you will have to maintain it..
what you can do is add a generic column in the select query:
EX:
select tb1.col1, tb1.col2, tb1.col3 ,
(
select 'Match' from table2 as tbl2
where tbl1.col1 = tbl2.col1 and tab1.col2 = tbl2.col2
)
from myTable as tbl1
Aaron's approach above worked perfectly for me. My update statement was slightly different because I needed to join based on two fields concatenated in one table to match a field in another table.
--update clients table cell field from custom table containing mobile numbers
update clients
set cell = m.Phone
from clients as c
inner join [dbo].[COSStaffMobileNumbers] as m
on c.Last_Name + c.First_Name = m.Name
Those who are using MYSQL
UPDATE table1 INNER JOIN table2 ON table2.id = table1.id SET table1.status = 0 WHERE table1.column = 20
Try:
UPDATE table1
SET CalculatedColumn = ( SELECT [Calculated Column]
FROM table2
WHERE table1.commonfield = [common field])
WHERE BatchNO = '110'

SQL Server update statement using a join on multiple columns

Having some trouble here.
Table 1:
CID, Name, HID
(001-233, Test1, 12345)
Table 2:
CID, Name, HID, Primary
(001-233, Test1, 12345, '')
Want to update Table2 where a join exists with Table1 with a constant value called 'Y'
So statement is as follows:
UPDATE T2 SET T2.Primary = 'Y'
FROM T2
INNER JOIN T1
ON (T1.CID = T2.CID
AND T1.HID = T2.HID)
This statement just ends up updating all the rows, it's like it only does a join on one id and not the other? I finally gave up and did a WHERE IN subquery with a single "id" by concatenating the two ide fields CID+HID. But I want to understand why this didnt work using the proper join.
Table1 is a CTE..
update t2
set (t2.primary) = (select 'Y' from t1 where T1.CID = T2.CID AND T1.HID = T2.HID)

refer to outside field value in subselect?

I want to do a query to update values that I forgot to copy over in a mass insert. However I'm not sure how to phrase it.
UPDATE table
SET text_field_1 = (SELECT text_field_2
FROM other_table
WHERE id = **current row in update statement, outside parens**.id )
How do I do this? It seems like a job for recursion.
Use:
UPDATE YOUR_TABLE
SET text_field_1 = (SELECT t.text_field_2
FROM other_table t
WHERE t.id = YOUR_TABLE.id)
Warning
If there's no supporting record in other_table, text_field_1 will be set to NULL.
Explanation
In standard SQL, you can't have table aliases on the table defined for the UPDATE (or DELETE) statement, so you need to use full table name to indicate the source of the column.
It's called a correlated subquery -- the correlation is be cause of the evaluation against the table from the outer query.
Clarification
MySQL (and SQL Server) support table aliases in UPDATE and DELETE statement, in addition to JOIN syntax:
UPDATE YOUR_TABLE a
JOIN OTHER_TABLE b ON b.id = a.id
SET a.text_field_1 = b.text_field_2
...is not identical to the provided query, because only the rows that match will be updated -- those that don't match, their text_field_1 values will remain untouched. This is equivalent to the provided query:
UPDATE YOUR_TABLE a
LEFT JOIN OTHER_TABLE b ON b.id = a.id
SET a.text_field_1 = b.text_field_2
If there is one ID field:
UPDATE updtable t1
SET t1.text_field_1 = (
SELECT t2.text_field_2
FROM seltable t2
WHERE t1.ID = t2.ID
)
;
UPDATE Table1, Tabl2
SET Table1.myField = Table2.SomeField
WHERE Table1.ID = Table2.ID
Note: I have not tried it.
This will only update records where IDs match.
Try this:
UPDATE table
SET text_field_1 = (SELECT text_field_2
FROM other_table
WHERE id = table.id )