I have the following table
id val
--------------
1 abc
2 xyz
3 abc
4 abc
Given the primary key(id) I need to be able to get all the rows with the same val as the row with the primary key.
Currently I have the following django code:
Table.objects.filter(val = Table.objects.get(id=1).val)
But this makes two queries to the database. I want to reduce this to a single database call. Is this possible in Django.
You can always use extra():
Table.objects.extra(where=['val=(select val from app_table where id=1)'])
This will result into single query:
SELECT
*
FROM
app_table
WHERE
val=(SELECT val FROM app_table WHERE id=1)
Related
I got lots of example to append/overwrite table in sql from AZ Databricks Notebook. But no single way to directly update, insert data using query or otherway.
ex. I want to update all row where (identity column)ID = 1143, so steps which I need to taken care are
val srMaster = "(SELECT ID, userid,statusid,bloburl,changedby FROM SRMaster WHERE ID = 1143) srMaster"
val srMasterTable = spark.read.jdbc(url=jdbcUrl, table=srMaster,
properties=connectionProperties)
srMasterTable.createOrReplaceTempView("srMasterTable")
val srMasterTableUpdated = spark.sql("SELECT userid,statusid,bloburl,140 AS changedby FROM srMasterTable")
import org.apache.spark.sql.SaveMode
srMasterTableUpdated.write.mode(SaveMode.Overwrite)
.jdbc(jdbcUrl, "[dbo].[SRMaster]", connectionProperties)
Is there any other sufficient way to achieve the same.
Note : Above code is also not working as SQLServerException: Could not drop object 'dbo.SRMaster' because it is referenced by a FOREIGN KEY constraint. , so it look like it drop table and recreate...not at all the solution.
You can use insert using a FROM statement.
Example: update values from another table in this table where a column matches.
INSERT INTO srMaster
FROM srMasterTable SELECT userid,statusid,bloburl,140 WHERE ID = 1143;
or
insert new values to rows where one of the existing column value matches
UPDATE srMaster SET userid = 1, statusid = 2, bloburl = 'https://url', changedby ='user' WHERE ID = '1143'
or just insert multiple values
INSERT INTO srMaster VALUES
(1, 10, 'https://url1','user1'),
(2, 11, 'https://url2','user2');
In SQL Server, you cannot drop a table if it is referenced by a FOREIGN KEY constraint. You have to either drop the child tables before removing the parent table, or remove foreign key constraints.
For a parent table, you can use the below query to get foreign key constraint names and the referencing table names:
SELECT name AS 'Foreign Key Constraint Name',
OBJECT_SCHEMA_NAME(parent_object_id) + '.' + OBJECT_NAME(parent_object_id) AS 'Child Table'
FROM sys.foreign_keys
WHERE OBJECT_SCHEMA_NAME(referenced_object_id) = 'dbo' AND
OBJECT_NAME(referenced_object_id) = 'PARENT_TABLE'
Then you can alter the child table and drop the constraint by its name using the below statement:
ALTER TABLE dbo.childtable DROP CONSTRAINT FK_NAME;
In my django project i had a table with a column named 'key_id'. Until today i had to group different values of this values, count it and display the largest result.
I did this:
maxpar = temp_test_keywords.objects.filter(main_id=test_id).values('key_id').annotate(total=Count('key_id')).order_by('-total').first()
maxMax = maxpar['total']
all done.
Today, we deceide to add another field to table, 'key_group'(could be 1,2,3,4) and now i have to use the same query for group and count max key_id field but related also for key_group.
For example before if in my table there was 5 record with key_id=187 and 3 with 112 my query had to return 5, now if for that 5 records 4 contain 'key_group=1' and one = 2 query have to return 4
Hope i was clear
Thanks in advance
Luke
I currently have Django models like this
MyFirstObject(models.Model):
some_field = models.BooleanField(default=False)
MySecondObject(models.Model):
first_object = models.ForeignKey(MyFirstObject, db_column='firstObjectId')
Because of various issues, our data integrity is corrupt. So, I need to find instances where MyFirstObject has been deleted, but MySecondObject still has a row w a foreign key to it.
The database would look similar to:
TABLE my_first_object
id someField
1 a
2 a
3 b
TABLE my_second_object
id firstObjectId
1 1
2 3
3 4
Notice row 3 of the TABLE my_second_object has an firstObjectID that does not have a corresponding record in the my_first_object table. I want to find all instances like that.
If I was doing raw SQL, I would do
SELECT my_second_object.id, my_second_object.firstObjectId
FROM my_second_object
LEFT JOIN ON ( my_second_object.firstObjectId = my_first_object.id )
WHERE my_first_object.id IS NULL
In Djago, I am trying
MySecondObject.objects.filter(my_first_object__id__isnull=true)
But when I look at the query that results, it is doing an inner join instead of left join. Does anyone have suggestions? Thanks!
Try like this:
first_object_ids = MyFirstObject.objects.values_list('id')
get_second_objects = MySecondObject.objects.exclude(my_first_object_id__in = first_object_ids)
I am using this link.
I have connected my cpp file with Eclipse to my Database with 3 tables (two simple tables
Person and Item
and a third one PersonItem that connects them). In the third table I use one simple primary and then two foreign keys like that:
CREATE TABLE PersonsItems(PersonsItemsId int not null auto_increment primary key,
Person_Id int not null,
Item_id int not null,
constraint fk_Person_id foreign key (Person_Id) references Person(PersonId),
constraint fk_Item_id foreign key (Item_id) references Items(ItemId));
So, then with embedded sql in c I want a Person to have multiple items.
My code:
mysql_query(connection, \
"INSERT INTO PersonsItems(PersonsItemsId, Person_Id, Item_id) VALUES (1,1,5), (1,1,8);");
printf("%ld PersonsItems Row(s) Updated!\n", (long) mysql_affected_rows(connection));
//SELECT newly inserted record.
mysql_query(connection, \
"SELECT Order_id FROM PersonsItems");
//Resource struct with rows of returned data.
resource = mysql_use_result(connection);
// Fetch multiple results
while((result = mysql_fetch_row(resource))) {
printf("%s %s\n",result[0], result[1]);
}
My result is
-1 PersonsItems Row(s) Updated!
5
but with VALUES (1,1,5), (1,1,8);
I would like that to be
-1 PersonsItems Row(s) Updated!
5 8
Can somone tell me why is this not happening?
Kind regards.
I suspect this is because your first insert is failing with the following error:
Duplicate entry '1' for key 'PRIMARY'
Because you are trying to insert 1 twice into the PersonsItemsId which is the primary key so has to be unique (it is also auto_increment so there is no need to specify a value at all);
This is why rows affected is -1, and why in this line:
printf("%s %s\n",result[0], result[1]);
you are only seeing 5 because the first statement failed after the values (1,1,5) had already been inserted, so there is still one row of data in the table.
I think to get the behaviour you are expecting you need to use the ON DUPLICATE KEY UPDATE syntax:
INSERT INTO PersonsItems(PersonsItemsId, Person_Id, order_id)
VALUES (1,1,5), (1,1,8)
ON DUPLICATE KEY UPDATE Person_id = VALUES(person_Id), Order_ID = VALUES(Order_ID);
Example on SQL Fiddle
Or do not specify the value for personsItemsID and let auto_increment do its thing:
INSERT INTO PersonsItems( Person_Id, order_id)
VALUES (1,5), (1,8);
Example on SQL Fiddle
I think you have a typo or mistake in your two queries.
You are inserting "PersonsItemsId, Person_Id, Item_id"
INSERT INTO PersonsItems(PersonsItemsId, Person_Id, Item_id) VALUES (1,1,5), (1,1,8)
and then your select statement selects "Order_id".
SELECT Order_id FROM PersonsItems
In order to achieve 5, 8 as you request, your second query needs to be:
SELECT Item_id FROM PersonsItems
Edit to add:
Your primary key is autoincrement so you don't need to pass it to your insert statement (in fact it will error as you pass 1 twice).
You only need to insert your other columns:
INSERT INTO PersonsItems(Person_Id, Item_id) VALUES (1,5), (1,8)
I tried with normal sql query
SELECT activity_shares.id FROM `activity_shares`
INNER JOIN (SELECT `activity_id` FROM `activity_shares`
GROUP BY `activity_id`
HAVING COUNT(`activity_id`) > 1 ) dup ON activity_shares.activity_id = dup.activity_id
Which gives me record id say 10 and 11
But same query I tried to do in Doctrine query builder,
$qb3=$this->getEntityManager()->createQueryBuilder('c')
->add('select','c.id')
->add('from','MyBundleDataBundle:ActivityShare c')
->innerJoin('c.activity', 'ca')
// ->andWhere('ca.id = c.activity')
->groupBy('ca.id')
->having('count(ca.id)>1');
Edited:
$query3=$qb3->getQuery();
$query3->getResult();
Generated SQL is:
SELECT a0_.id AS id0 FROM activity_shares a0_
INNER JOIN activities a1_ ON a0_.activity_id = a1_.id
GROUP BY a1_.id HAVING count(a1_.id) > 1
Gives only 1 record that is 10.I want to get both.I'm not getting idea where I went wrong.Any idea?
My tables structure is:
ActivityShare
+-----+---------+-----+---
| Id |activity |Share| etc...
+-----+---------+-----+----
| 1 | 1 |1 |
+-----+---------+-----+---
| 2 | 1 | 2 |
+-----+---------+-----+---
Activity is foreign key to Activity table.
I want to get Id's 1 and 2
Simplified SQL
first of all let me simplify that query so it gives the same result :
SELECT id FROM `activity_shares`
GROUP BY `id`
HAVING COUNT(`activity_id`) > 1
Docrtrine QueryBuilder
If you store the id of the activty in the table like you sql suggests:
You can use the simplified SQL to build a query:
$results =$this->getEntityManager()->createQueryBuilder('c')
->add('select','c.id')
->add('from','MyBundleDataBundle:ActivityShare c')
->groupBy('c.id')
->having('count(c.activity)>1');
->getResult();
If you are using association tables ( Doctrine logic)
here you will have to use join but the count may be tricky
Solution 1
use the associative table like an entitiy ( as i see it you only need the id)
Let's say the table name is activityshare_activity
it will have two fields activity_id and activityshare_id, if you find a way to add a new column id to that table and make it Autoincrement + Primary the rest is easy :
the new entity being called ActivityShareActivity
$results =$this->getEntityManager()->createQueryBuilder('c')
->add('select','c.activityshare_id')
->add('from','MyBundleDataBundle:ActivityShareActivity c')
->groupBy('c.activityshare_id')
->having('count(c.activity_id)>1');
->getResult();
the steps to add the new identification column to make it compatible with doctrine (you need to do this once):
add the column (INT , NOT NULL) don' t put the autoincrement yet
ALTER TABLE tableName ADD id INT NOT NULL
Populate the column using a php loop like for
Modify the column to be autoincrement
ALTER TABLE tableName MODIFY id INT NOT NULL AUTO_INCREMENT
Solution2
The correction to your query
$result=$this->getEntityManager()->createQueryBuilder()
->select('c.id')
->from('MyBundleDataBundle:ActivityShare', 'c')
->innerJoin('c.activity', 'ca')
->groupBy('c.id') //note: it's c.id not ca.id
->having('count(ca.id)>1')
->getResult();
I posted this one last because i am not 100% sure of the output of having+ count but it should word just fine :)
Thanks for your answers.I finally managed to get answer
My Doctrine query is:
$subquery=$this->getEntityManager()->createQueryBuilder('as')
->add('select','a.id')
->add('from','MyBundleDataBundle:ActivityShare as')
->innerJoin('as.activity', 'a')
->groupBy('a.id')
->having('count(a.id)>1');
$query=$this->getEntityManager()->createQueryBuilder('c')
->add('select','c.id')
->add('from','ChowzterDataBundle:ActivityShare c')
->innerJoin('c.activity', 'ca');
$query->andWhere($query->expr()->in('ca.id', $subquery->getDql()))
;
$result = $query->getQuery();
print_r($result->getResult());
And SQL looks like:
SELECT a0_.id AS id0 FROM activity_shares a0_ INNER JOIN activities a1_ ON a0_.activity_id = a1_.id WHERE a1_.id IN (SELECT a2_.id FROM activity_shares a3_ INNER JOIN activities a2_ ON a3_.activity_id = a2_.id GROUP BY a2_.id HAVING count(a2_.id) > 1