How to select more than one value from a 'non-existing' table.
For example:
SELECT ('val1', 'val2') as "test"
How to make a column "test" with two values/rows val1 and val2?
To temporarily generate rows with values, PostgreSQL has following options:
VALUES Lists like VALUES (1, 'one'), (2, 'two'), (3, 'three');
WITH Queries (Common Table Expressions) common-table-expression
CREATE TABLE TEMPORARY to create a table for temporary use in this session
For small numbers of rows I would suggest the VALUES expression.
For more rows and usage in complex queries I would suggest the temporary table.
See also:
Temporary table postgresql function
A Step-by-Step Guide To PostgreSQL Temporary Table
PostgreSQL Common Table Expressions vs a temporary table? - Database Administrators Stack Exchange
you can use union two rows in table like below code:
select 'val1' as "test"
union
select 'val2' as "test"
If you use SQL Server family, you can use a query similar to this :
declare #tmpTable as table (test varchar(50))
insert into #tmpTable
select 'val' Go 100
now you can use #tmpTable
Related
I've created a table in Databricks that is mapped to a table hosted in an Azure SQL DB. I'm trying to do a very simple insert statement on a small table, but an identity column is giving me issues. This table has the aforementioned identity column and three additional columns.
I first tried something similar to below:
%sql
INSERT INTO tableName (col2, col3, col4)
VALUES (1, 'Test Value', '2018-11-16')
That was giving me a syntax error, so I did some searching and learned that Hive SQL doesn't allow you to specify columns for an INSERT statement. So then I tried something like below as a test:
%sql
INSERT INTO tableName
VALUES (100, 1, 'Test Value', '2018-11-16')
That gives me an error message that I can't insert explicit values into an identity column, but that's what I expected to happen.
If I can't specify the columns for my INSERT statement, how do I avoid issues when I have an identity column? I just want to insert values for the non-identity columns, and I want the ID column to continue incrementing like normal. The above example is extremely watered-down. I will need to do much larger insertions based on SELECT statements eventually, so any solution involving toggling on IDENTITY_INSERT probably isn't feasible.
Below is how we can create a table with an identity column -
CREATE TABLE table_name
(column_name1 data_type GENERATED ALWAYS AS IDENTITY,
column_name2......)
Below are the two ways how we can insert the data into the table with the Identity column -
First way -
INSERT INTO T2 (CHARCOL2)
SELECT CHARCOL1 FROM T1;
Second way -
INSERT INTO T2 (CHARCOL2,IDENTCOL2) OVERRIDING USER VALUE
SELECT * FROM T1;
Links for reference-
Create table - https://docs.databricks.com/sql/language-manual/sql-ref-syntax-ddl-create-table-using.html
Insert into table - https://www.ibm.com/docs/en/db2-for-zos/11?topic=statement-rules-inserting-data-into-identity-column
I have a table table1 with columns id,value1 and value2.
Also I have a query
INSERT INTO table1(value1,value2) SELECT value3,value4 FROM table2 RETURNING id
that returns set of ids.
I want to store return values (these ids) in some temp table. Something like that:
INSERT INTO TEMP temp1 INSERT INTO table1(value1,value2) SELECT value3,value4 FROM table2 RETURNING id
How can I do it?
DBMS is PostgreSQL
with inserted as (
INSERT INTO table1 (value1,value2)
SELECT value3,value4
FROM table2
RETURNING id
)
insert into temp
select id
from inserted;
This requires Postgres 9.2 or later.
Two options.
If you need it just for one follow-up query, a with statement (see the horse's answer) is the easiest.
If you need it for more than one follow-up query, the other option is to not use insert ... returning, but rather create table as:
CREATE TEMPORARY TABLE foo AS
SELECT value3,value4 FROM table2
Caveats: if necessary, create the indexes you need on the table -- and analyze it if you do.
So I have this temp table that has structure like:
col1 col2 col3 col3
intID1 intID2 intID3 bitAdd
I am doing a union of the values of this temp table with a select query and storing
it into the same temp table.The thing is col3 is not part of the union query I will
need it later on to update the table.
So I am doing like so:
Insert into #temptable
(
intID1,
intID2,
intID3
)
select intID1,intID2,intID3
From
#temptable
UNION
select intID1,intID2,intID3
From
Table A
Issue is that I want only the rows that are not already existing in the temp table to be added.Doing it this way will add a duplicate of the already existing row(since union will return one row)How do I insert only those rows not existing in the current temp table in my union query?
Use MERGE:
MERGE INTO #temptable tmp
USING (select intID1,intID2,intID3 From Table A) t
ON (tmp.intID1 = t.intID1 and tmp.intID2 = t.intID2 and tmp.intID3 = t.intID3)
WHEN NOT MATCHED THEN
INSERT (intID1,intID2,intID3)
VALUES (t.intID1,t.intID2,t.intID3)
Nice and simple with EXCEPT
INSERT INTO #temptable (intID1, intID2, intID3)
SELECT intID1,intID2,intID3 FROM TableA
EXCEPT
SELECT intID1,intID2,intID3 FROM #temptable
I see where you are coming from. In most programming languages #temptable would be a variable (a relation variable or relvar for short) to which you would assign a value (a relation value) thus:
#temptable := #temptable UNION A
In the relational model, this would achieve the desired result because a relation has no duplicate rows by definition.
However, SQL is not truly relational and does not support assignment. Instead, you are required to add rows to a table using SQL DML INSERT statements (which is not so bad: the users of a truly relational database language, if we had one, would no doubt demand a similar shorthand for relational assignment!) but you are also required to do the test for duplicates yourself.
The answers from Daniel Hilgarth and Joachim Isaksson both look good. It's good practice to have two good, logically sound candidate answers then look for criteria (usually performance under typical load) to eliminate one (but retaining it commented out for future re-testing!)
I have created table #temp with columns id as int identity(1,1) and name as varchar.
Say suppose I am writing the following 2 different statements for inserting rows:
insert into #temp (name) select ('Vikrant') ;
insert #temp (name) select ('Vikrant')
I want to ask what is the difference between these two types of insert statements?
Is there really any difference in between these insertions?
From the MSDN documentation:
[INTO]
Is an optional keyword that can be used between INSERT and the target table.
There is no difference between the two statements.
One question about how to t-sql program the following query:
Table 1
I insert 400.000 mobilephonenumbers in a table with two columns. The number to insert and identity id.
Table 2
The second table is called SendList. It is a list with 3columns, a identity id, a List id, and a phonenumberid.
Table 3
Is called ListInfo and contains PK list id. and info about the list.
My question is how should I using T-sql:
Insert large list with phonenumbers to table 1, insert the generated id from the insert of phonenum. in table1, to table 2. AND in a optimized way. It cant take long time, that is my problem.
Greatly appreciated if someone could guide me on this one.
Thanks
Sebastian
What version of SQL Server are you using? If you are using 2008 you can use the OUTPUT clause to insert multiple records and output all the identity records to a table variable. Then you can use this to insert to the child tables.
DECLARE #MyTableVar table(MyID int);
INSERT MyTabLe (field1, field2)
OUTPUT INSERTED.MyID
INTO #MyTableVar
select Field1, Field2 from MyOtherTable where field3 = 'test'
--Display the result set of the table variable.
Insert MyChildTable (myID,field1, field2)
Select MyID, test, getdate() from #MyTableVar
I've not tried this directly with a bulk insert, but you could always bulkinsert to a staging table and then use the processs, described above. Inserting groups of records is much much faster than one at a time.