Does Big Query support operations like "REPLACE INSERT" or something related to that?
If I run a query like this twice:
INSERT INTO table(column1) VALUES(1)
It'll create a duplicated row, is it possible to insert a row only if a column with the same value does not exist?
Thanks!
Below should make it
#standardSQL
INSERT INTO yourTable(column1)
SELECT value FROM (SELECT 1 AS value)
LEFT JOIN yourTable
ON column1 = value
WHERE column1 IS NULL
Does this work for you?
INSERT INTO table(column1)
WITH s AS (SELECT 1 src)
SELECT src FROM s WHERE NOT EXISTS (
SELECT * FROM table t WHERE t.column1 = s.src
)
Related
I'm using the following query to insert a record into a table only if it does not exist:
INSERT INTO tblExample (exampleColumn)
SELECT 'test' FROM tblExample
WHERE NOT EXISTS (SELECT 1 FROM tblExample where exampleColumn = 'test');
It works fine as long as there is at least 1 record in the table. If there are no records, it will not insert the record into the table.
Can anyone see what is wrong with my query?
Thanks!
Tested with Derby 10.12
INSERT INTO tblExample (exampleColumn)
SELECT *
from (values ('test')) as x(col)
WHERE NOT EXISTS (SELECT 1
FROM tblExample t
where t.exampleColumn = x.col);
Try this,
INSERT INTO tblExample (exampleColumn)
SELECT Value FROM ( SELECT 'test' Value) T1
WHERE NOT EXISTS (SELECT 1 FROM tblExample where exampleColumn = 'test')
Or you can use this
INSERT INTO tblExample (exampleColumn)
SELECT Value FROM ( SELECT 'test' Value) T1
LEFT JOIN tblExample ON exampleColumn = Value
WHERE exampleColumn IS NULL
Query is :
INSERT INTO user (id, name, date)
SELECT 23,test,DATE('2013-02-12')
FROM contact
WHERE NOT EXISTS ( SELECT 1 FROM user WHERE id = 23 )
thanks for your help. I have found that the best way to add a record if it doesn't already exist (even when there are no records in the table) is by using the following statement:
INSERT INTO tblExample(exampleColumn)
(SELECT 'test' FROM tblExample WHERE exampleColumn='test' HAVING COUNT(*)=0);
Your first query "SELECT 'test' FROM tblExample" will return 0 rows if there is not record in a table.
Use bellow code.
IF NOT EXISTS(SELECT * FROM tblExample where exampleColumn='test')
insert into tblExample(exampleColumn) values ('test')
I try to insert into table with 1 column is (select from table).
I should copy all the id to table1 with 1 column is (select from table )
This not working:
insert into table1 (id,resoucrce,rate) values ((select id from table2),0,0)
I want to do something like that insert all the id from table to another table with default values.
Use insert . . . select:
insert into table1 (id, resource, rate)
select id, 0, 0
from table2;
For copy the content of one table to another table within the same database use this :-
INSERT INTO TARGET_TABLE (`col1`,`col2`) SELECT `col1`,`col2` FROM SOURCE_TABLE;
or your query like that :-
Insert into table1 (id, resource, rate) select id, 0, 0 from table2;
You should focus "values" keyword;
values ((select id from table2),0,0)
When you use values(, , ,) you have to specify value columns. But you're trying to pass both resultset and single values together. That's why you get an error. You should only pass single values...
If its clear for you; you can easily find the correct sql syntax.
So for each distinct value in a column of one table I want to insert that unique value into a row of another table.
list = select distinct(id) from table0
for distinct_id in list
insert into table1 (id) values (distinct_id)
end
Any ideas as to how to go about this?
Whenever you think about doing something in a loop, step back, and think again. SQL is optimized to work with sets. You can do this using a set-based query without the need to loop:
INSERT dbo.table1(id) SELECT DISTINCT id FROM dbo.table0;
There are some edge cases where looping can make more sense, but as SQL Server matures and more functionality is added, those edge cases get narrower and narrower...
insert into table1 (id)
select distinct id from table0
The following statement works with me.
insert into table1(col1, col2) select distinct on (col1) col1 col2 from table0
The below query will also check the existing data in the Table2.
INSERT INTO Table2(Id) SELECT DISTINCT Id FROM Table1 WHERE Id NOT IN(SELECT Id FROM Table2);
Other Simple way to copy distinct data with multiple columns from one table to other
Insert into TBL2
Select * from (Select COL1, ROW_NUMBER() over(PARTITION BY COL1 Order By COL1) AS COL2 From TBL1)T
where T.COL2 = 1
Is it possible to do something like this:
INSERT INTO table(col1, col2) VALUES(something_from_another_table, value);
With something_from_another_table being a SQL command? Like, is there something I can do that's equivelant to:
INSERT INTO table(col1, col2) VALUES((SELECT value FROM table2 WHERE id = 3), value);
Yes
INSERT INTO table(col1, col2)
SELECT value1, 'value2' FROM table2 WHERE id = 3
Where value1 is the value from the 'other table' and value2 is a constant that you've included in that select statement.
Try this:
INSERT INTO table(col1, col2)
SELECT table2.value1, value2 FROM table2 WHERE table2.id = 3;
http://dev.mysql.com/doc/refman/5.1/en/insert-select.html
take a look especially in the examples.
I would recommend reading full syntax of SELECT, UPDATE, DELETE and INSERT SQL commands to begin with. Then expand to subqueries and DDL.
Go slowly and work out examples.
You definately can. It should work similar as the example below;
INSERT INTO Store_Information (store_name, Sales, Date)
(SELECT store_name, Sales, Date FROM Sales_Information WHERE Year(Date) = 2010)
when you specify the keyword "Values" on the insert statement you are trying to insert just a value. the current way to do that is assigning the value of the "something_from_another_table" into a variable and then, make your insert
DECLARE #ANYVALUE AS VARCHAR(40)
SELECT #ANYVALUE = ANYFIELD FROM table2 WHERE id = 3
INSERT INTO table1 (FIELD1, FIELD2) VALUES(#ANYVALUE, VALUE2)
On this way always will insert one record. the other correct way will insert n record as the where statement can filter.
INSERT INTO Store_Information (store_name, Sales, Date)
(SELECT store_name, Sales, Date FROM Sales_Information WHERE Year(Date) = 2010)
I have a table with say 3 columns. There's no primary key so there can be duplicate rows. I need to just keep one and delete the others. Any idea how to do this is Sql Server?
I'd SELECT DISTINCT the rows and throw them into a temporary table, then drop the source table and copy back the data from the temp.
EDIT: now with code snippet!
INSERT INTO TABLE_2
SELECT DISTINCT * FROM TABLE_1
GO
DELETE FROM TABLE_1
GO
INSERT INTO TABLE_1
SELECT * FROM TABLE_2
GO
Add an identity column to act as a surrogate primary key, and use this to identify two of the three rows to be deleted.
I would consider leaving the identity column in place afterwards, or if this is some kind of link table, create a compound primary key on the other columns.
The following example works as well when your PK is just a subset of all table columns.
(Note: I like the approach with inserting another surrogate id column more. But maybe this solution comes handy as well.)
First find the duplicate rows:
SELECT col1, col2, count(*)
FROM t1
GROUP BY col1, col2
HAVING count(*) > 1
If there are only few, you can delete them manually:
set rowcount 1
delete from t1
where col1=1 and col2=1
The value of "rowcount" should be n-1 times the number of duplicates. In this example there are 2 dulpicates, therefore rowcount is 1. If you get several duplicate rows, you have to do this for every unique primary key.
If you have many duplicates, then copy every key once into anoher table:
SELECT col1, col2, col3=count(*)
INTO holdkey
FROM t1
GROUP BY col1, col2
HAVING count(*) > 1
Then copy the keys, but eliminate the duplicates.
SELECT DISTINCT t1.*
INTO holddups
FROM t1, holdkey
WHERE t1.col1 = holdkey.col1
AND t1.col2 = holdkey.col2
In your keys you have now unique keys. Check if you don't get any result:
SELECT col1, col2, count(*)
FROM holddups
GROUP BY col1, col2
Delete the duplicates from the original table:
DELETE t1
FROM t1, holdkey
WHERE t1.col1 = holdkey.col1
AND t1.col2 = holdkey.col2
Insert the original rows:
INSERT t1 SELECT * FROM holddups
btw and for completeness: In Oracle there is a hidden field you could use (rowid):
DELETE FROM our_table
WHERE rowid not in
(SELECT MIN(rowid)
FROM our_table
GROUP BY column1, column2, column3... ;
see: Microsoft Knowledge Site
Here's the method I used when I asked this question -
DELETE MyTable
FROM MyTable
LEFT OUTER JOIN (
SELECT MIN(RowId) as RowId, Col1, Col2, Col3
FROM MyTable
GROUP BY Col1, Col2, Col3
) as KeepRows ON
MyTable.RowId = KeepRows.RowId
WHERE
KeepRows.RowId IS NULL
This is a way to do it with Common Table Expressions, CTE. It involves no loops, no new columns or anything and won't cause any unwanted triggers to fire (due to deletes+inserts).
Inspired by this article.
CREATE TABLE #temp (i INT)
INSERT INTO #temp VALUES (1)
INSERT INTO #temp VALUES (1)
INSERT INTO #temp VALUES (2)
INSERT INTO #temp VALUES (3)
INSERT INTO #temp VALUES (3)
INSERT INTO #temp VALUES (4)
SELECT * FROM #temp
;
WITH [#temp+rowid] AS
(SELECT ROW_NUMBER() OVER (ORDER BY i ASC) AS ROWID, * FROM #temp)
DELETE FROM [#temp+rowid] WHERE rowid IN
(SELECT MIN(rowid) FROM [#temp+rowid] GROUP BY i HAVING COUNT(*) > 1)
SELECT * FROM #temp
DROP TABLE #temp
This is a tough situation to be in. Without knowing your particular situation (table size etc) I think that your best shot is to add an identity column, populate it and then delete according to it. You may remove the column later but I would suggest that you should keep it as it is really a good thing to have in the table
After you clean up the current mess you could add a primary key that includes all the fields in the table. that will keep you from getting into the mess again.
Of course this solution could very well break existing code. That will have to be handled as well.
Can you add a primary key identity field to the table?
Manrico Corazzi - I specialize in Oracle, not MS SQL, so you'll have to tell me if this is possible as a performance boost:-
Leave the same as your first step - insert distinct values into TABLE2 from TABLE1.
Drop TABLE1. (Drop should be faster than delete I assume, much as truncate is faster than delete).
Rename TABLE2 as TABLE1 (saves you time, as you're renaming an object rather than copying data from one table to another).
Here's another way, with test data
create table #table1 (colWithDupes1 int, colWithDupes2 int)
insert into #table1
(colWithDupes1, colWithDupes2)
Select 1, 2 union all
Select 1, 2 union all
Select 2, 2 union all
Select 3, 4 union all
Select 3, 4 union all
Select 3, 4 union all
Select 4, 2 union all
Select 4, 2
select * from #table1
set rowcount 1
select 1
while ##rowcount > 0
delete #table1 where 1 < (select count(*) from #table1 a2
where #table1.colWithDupes1 = a2.colWithDupes1
and #table1.colWithDupes2 = a2.colWithDupes2
)
set rowcount 0
select * from #table1
What about this solution :
First you execute the following query :
select 'set rowcount ' + convert(varchar,COUNT(*)-1) + ' delete from MyTable where field=''' + field +'''' + ' set rowcount 0' from mytable group by field having COUNT(*)>1
And then you just have to execute the returned result set
set rowcount 3 delete from Mytable where field='foo' set rowcount 0
....
....
set rowcount 5 delete from Mytable where field='bar' set rowcount 0
I've handled the case when you've got only one column, but it's pretty easy to adapt the same approach tomore than one column. Let me know if you want me to post the code.
How about:
select distinct * into #t from duplicates_tbl
truncate duplicates_tbl
insert duplicates_tbl select * from #t
drop table #t
I'm not sure if this works with DELETE statements, but this is a way to find duplicate rows:
SELECT *
FROM myTable t1, myTable t2
WHERE t1.field = t2.field AND t1.id > t2.id
I'm not sure if you can just change the "SELECT" to a "DELETE" (someone wanna let me know?), but even if you can't, you could just make it into a subquery.