I want to insert a new record if the record is not present in the table
For that I am using below query in Teradata
INSERT INTO sample(id, name) VALUES('12','rao')
WHERE NOT EXISTS (SELECT id FROM sample WHERE id = '12');
When I execute the above query I am getting below error.
WHERE NOT EXISTS
Failure 3706 Syntax error: expected something between ')' and the 'WHERE' keyword.
Can anyone help with the above issue. It will be very helpful.
You can use INSERT INTO ... SELECT ... as follows:
INSERT INTO sample(id,name)
select '12','rao'
WHERE NOT EXISTS (SELECT id FROM sample WHERE id = '12');
You can also create the primary/unique key on id column to avoid inserting duplicate data in id column.
I would advise writing the query as:
INSERT INTO sample (id, name)
SELECT id, name
FROM (SELECT 12 as id, 'rao' as name) x
WHERE NOT EXISTS (SELECT 1 FROM sample s WHERE s.id = x.id);
This means that you do not need to repeat the constant value -- such repetition can be a cause of errors in queries. Note that I removed the single quotes. id looks like a number so treat it as a number.
The uniqueness of ids is usually handled using a unique constraint or index:
alter table sample add constraint unq_sample_id unique (id);
This makes sure that the database ensures uniqueness. Your approach can fail if two inserts are run at the same time with the same id. An attempt to insert a duplicates returns an error (which the exists can then avoid).
In practice, id columns are usually generated automatically by the database. So the create table statement would look more like:
id integer generated by default as identity
And the insert would look like:
insert into sample (name)
values (name);
If id is the Primary Index of the table you can use MERGE:
merge into sample as tgt
using VALUES('12','rao') as src (id, name)
on src.id = tgt.id
when not matched
then insert (src.id,src.name)
Related
I'm creating a C# Winforms application for recipe management in an industrial environment.
I created a SQL Server table with 130 columns. The table contains a column called CheckData (of datatype Timestamp), which I use to detect changes made to a row.
If I insert a new row to that table all works fine. The code I use is:
INSERT INTO tablename (Column1, column2, column3, column4)
VALUES (value1, value2, value3, value4)
I just assign values to major columns, the others get their default value. I do not assign a value to the timestamp field since it's written by the system.
Additionally, I want to copy a row from this table to the same table (duplicate a data record).
I copy the source row to a temporary table, drop the ID (primary key) and the timestamp fields in that temporary table and try to insert that only row in the temporary table into the table. This fails.
Here's the code:
SELECT *
INTO #temptable
FROM tablename
WHERE Recipe_No = 8;
ALTER TABLE #temptable DROP COLUMN ID, CHECKDATA;
ALTER TABLE #temptable REBUILD;
UPDATE #temptable
SET Recipe_No = 9, Recipe_Name = 'Test'
WHERE Recipe_No = 8;
INSERT INTO tablename
SELECT * FROM #temptable;
I don't understand where the difference is between inserting a new row thru INSERT INTO xxx (yyy) VALUES (zzz) and INSERT INTO xxx SELECT * FROM yyy. In both cases I don't try to write the timestamp value in the new row.
Does anybody have an idea what I'm missing here?
I don't understand where the difference is between inserting a new row thru INSERT INTO xxx (yyy) VALUES (zzz) and INSERT INTO xxx SELECT * FROM yyy.
With this,
INSERT INTO xxx SELECT * FROM yyy.
you are failing to specify the column mappings from the SELECT to the target table. You should always use
INSERT INTO xxx (Column1, Column2, . . .)
SELECT (Column1, Column2, . . .)
FROM yyy
Here's a simplified example of what you're attempting:
drop table if exists t
create table t(id int, a int)
insert into t(id,a) values (1,1)
select * into #t from t where id = 1
alter table #t drop column id
insert into t select * from #t
and it will fail with
Msg 213, Level 16, State 1, Line 12
Column name or number of supplied values does not match table definition.
because the temp table doesn't even have the same number of columns. And even if it did, you wouldn't know for sure that the column mappings were correct.
It is failing because essentially your command
INSERT INTO tablename SELECT * FROM #temptable;";
Is telling SQL - "Insert everything into this table from this temp table."
While you can work around this, I would say why don't you just try inserting into only the columns made available in your current table with only the values you would like to include. Instead of needing to drop the columns/values, you just don't import it to begin with.
An alternative - if you can write to a helper table, it may be beneficial to INSERT INTO that helper table, as opposed to a temp table, the values you have. Then transform that helper table, and THEN you can do INSERT INTO final_table SELECT * FROM helper. This should give you the results you're looking for.
I hope this is helpful, and I hope it explains why your current command is failing.
Hi I'm running into the following problem on SQlite3
I have a simple table
CREATE TABLE TestTable (id INT, cnt INT);
There are some rows already in the table.
I have some data I want to be inserted into the table: {(id0, cnt0), (id1, cnt1)...}
I want to insert data into the table, on id conflict, update TestTable.cnt = TestTable.cnt + value.cnt
(values.cnt is cnt0, cnt1 ... basically my data to be inserted)
*** But the problem is, there is no primary or unique constraint on id, and I am not allowed to change it!
What I currently have :
In my program I loop through all the values
UPDATE TestTABLE SET count = count + value.cnt WHERE id = value.id;
if (sqlite3_changes() == 0)
INSERT INTO MyTable (id, cnt) values (value.id, value.cnt);
But the problem is, with a very large dataset, doing 2 queries for each data entry takes too long. I'm trying to bundle multiple entries together into one call.
Please let me know if you have questions about my description, thank you for helping!
If you are able to create temporary tables, then do the following. Although I don't show it here, I suggest wrapping all this in a transaction. This technique will likely increase efficiency even if you are also able to add a temporary unique index. (In that case you could use an UPSERT with source data in the temporary table.)
CREATE TEMP TABLE data(id INT, cnt INT);
Now insert the new data into the temporary table, whether by using the host-language data libraries or crafting an insert statement similar to
INSERT INTO data (id, cnt)
VALUES (1, 100),
(2, 200),
(5, 400),
(7, 500);
Now update all existing rows using the single UPDATE statement. SQLite does not have a convenient syntax for joining tables and/or providing a source query for an UPDATE statement. However, one can use nested statement to provide similar convenience:
UPDATE TestTable AS tt
SET cnt = cnt + ifnull((SELECT cnt FROM data WHERE data.id == tt.id), 0)
WHERE tt.id IN (SELECT id FROM data);
Note that the two nested queries are independent of each other. In fact, one could eliminate the WHERE clause altogether and get the same results for this simple case. The WHERE clause is simply to make it more efficient, only attempting to update matching id's. The other subquery in the SET clause also specifies a match on id, but alone it would still allow updates of rows that don't have a match, defaulting to a null value and being converted to 0 (by isnull() function) for a no-op. By the way, without the isnull() function, the sum would result in null and would overwrite non-null values.
Finally, insert only rows with non-existing id values:
INSERT INTO TestTable (id, cnt)
SELECT data.id, data.cnt
FROM data LEFT JOIN TestTable
ON data.id == TestTable.id
WHERE TestTable.id IS NULL;
I have created tables T1 with columns( id as Primary key and name) and T2 with columns( id as primary key, name, t_id as foreign key references T1(id)) . I Inserted some values from inputs from a Windows form. After querying SELECT * FROM T2; using isql, all the values in the foreign key column are null instead of duplicating values in T1(id) because of the relationship created. Is they anything I have left out or need to add? The primary key of both tables are autoincremented.
You are confusing auto-incremented keys and relationship uses.
Auto-incremented keys (or generally talking, fields) just help you when you are inserting a new record on the table of the key. But when you are inserting a new record that makes a reference to a record in another table, then you must specify that record, using the foreign key field. Or in your case, the user that is inserting the "name" in T2 must say which one record on T1 that "name" in T2 is making a reference.
Your confusion on the relationship is that you are thinking that an established relationship will enforce the use of that values automatically. But the relationship just enforce the validation of the values. So, the field t_id in T2 will not use the value of the last record of T1 automatically. But if you try to insert a value that do not exist in T1 in the field t_id, the relationship will not let you do.
So, answering your question, what you left out and need to add?
You left out the part of the code that insert the value on the t_id field of T2 table.
Let me try to explain using an example that is more common.
The most common case of this is that the application insert first the T1 record and then when the user is inserting T2, the application provide a way to the user to choose which one T1 record his T2 record is referencing.
Suppose T1 is a publishers table and T2 is a book table. User insert a publisher, and when it is inserting a book it can choose which one publisher publish that book.
Field "ID" of Customers will be AUTOINCREMENT by default in table create using Event BeforeInsert on table CUSTOMERS. LOOK AT
CREATE TRIGGER nametrigger FOR nametable
ACTIVE BEFORE INSERT POSITION 0
AS
BEGIN
IF (NEW.ID IS NULL) THEN BEGIN
NEW.ID = GEN_ID(GEN_PK_ID, 1);
END
END
Now one new record in Customers
INSERT INTO Customers (CustomerName, ContactName, Address, City, PostalCode, Country)
VALUES ('Cardinal','Tom B. Erichsen','Skagen 21','Stavanger','4006','Norway');
Then ID will be automaticaly one sequencial number from 1 up to last integer or smallint or bigint as you defined in your create table (pay attencion that ID field is not include in FIELDS and VALUES) because TRIGGER
now you can use the dataset (obj) options to link the table MATER and DETAIL see in help delphi
or in SQL you can to use PARAMS FIELDS
later insert one new record in table MASTER try...
INSERT INTO xTable2 (IDcustomersField, ..., ..., ...., ....)
VALUES ( :IDcustomersField, ..., ..., ...., ....);
xTable2 may using one field ID (Primary Key) autoincrement too. this help when DELETING or UPDATING fileds in this table
Then you can say the value to :IDcustomersField in table detail using
xQuery.PARAM( 0 ).value or xQuery.PARAMBYNAME( IDcustomersField).value (here im using Query obj as example )
you can to use example with DATASOURCE in code to say the value for IDcustomersField
can to use
Events in SQL
can to use
PROCEDURE IN SQL
DONT FORGOT
you have to create Relationship between two table ( REFERENCIAL INTEGRITY and PRIMARY KEY in mater table ) NOT NULL FOR TWO FIELDS ON TABLES
I believe that understand me about my poor explanation (i dont speak english
You need to insert the values for t_id manually, after you get the ID's value from the main table T1.
Depending on your logic in the database you also can use a trigger or a stored procedure. Give us more information about what values you expect to have in NAME field in T2 after the insert? Are they duplicates from T1 or independent from T1?
If T1.NAME=T2.NAME, you can automate the process with a trigger
CREATE OR ALTER TRIGGER TR_T1_AI0 FOR T1
ACTIVE AFTER INSERT POSITION 0
AS
BEGIN
INSERT INTO T2(NAME, T_ID)
VALUES (NEW.NAME, NEW.ID);
END
If T2.NAME's value is different from T1.NAME you can use a stored procedure with parameters both names:
CREATE ORA ALTER PROCEDURE XXXX(
P_NAME_T1 TYPE OF T1.NAME,
P_NAME_T2 TYPE OF T2.NAME)
AS
DECLARE VARIABLE L_ID TYPE OF T1.ID;
BEGIN
INSERT INTO T1(NAME)
VALUES (:p_NAME_T1)
RETURNING ID INTO:L_ID;
INSERT INTO T2(NAME, T_ID)
VALUES (:P_NAME_T2, :l_ID);
END
You can use both statements from the stored procedure directly in your program if it supports the returning syntax. If not, you need an additional query with SELECT NEXT VALUE FOR GENERATOR_FOR_T1 FROM RDB$DATABASE; and use the value returned from it in both INSERT statements.
I am trying to copy a record in a table and change a few values with a stored procedure in SQL Server 2005. This is simple, but I also need to copy relationships in other tables with the new primary keys. As this proc is being used to batch copy records, I've found it difficult to store some relationship between old keys and new keys.
Right now, I am grabbing new keys from the batch insert using OUTPUT INTO.
ex:
INSERT INTO table
(column1, column2,...)
OUTPUT INSERTED.PrimaryKey INTO #TableVariable
SELECT column1, column2,...
Is there a way like this to easily get the old keys inserted at the same time I am inserting new keys (to ensure I have paired up the proper corresponding keys)?
I know cursors are an option, but I have never used them and have only heard them referenced in a horror story fashion. I'd much prefer to use OUTPUT INTO, or something like it.
If you need to track both old and new keys in your temp table, you need to cheat and use MERGE:
Data setup:
create table T (
ID int IDENTITY(5,7) not null,
Col1 varchar(10) not null
);
go
insert into T (Col1) values ('abc'),('def');
And the replacement for your INSERT statement:
declare #TV table (
Old_ID int not null,
New_ID int not null
);
merge into T t1
using (select ID,Col1 from T) t2
on 1 = 0
when not matched then insert (Col1) values (t2.Col1)
output t2.ID,inserted.ID into #TV;
And (actually needs to be in the same batch so that you can access the table variable):
select * from T;
select * from #TV;
Produces:
ID Col1
5 abc
12 def
19 abc
26 def
Old_ID New_ID
5 19
12 26
The reason you have to do this is because of an irritating limitation on the OUTPUT clause when used with INSERT - you can only access the inserted table, not any of the tables that might be part of a SELECT.
Related - More explanation of the MERGE abuse
INSERT statements loading data into tables with an IDENTITY column are guaranteed to generate the values in the same order as the ORDER BY clause in the SELECT.
If you want the IDENTITY values to be assigned in a sequential fashion
that follows the ordering in the ORDER BY clause, create a table that
contains a column with the IDENTITY property and then run an INSERT ..
SELECT … ORDER BY query to populate this table.
From: The behavior of the IDENTITY function when used with SELECT INTO or INSERT .. SELECT queries that contain an ORDER BY clause
You can use this fact to match your old with your new identity values. First collect the list of primary keys that you intend to copy into a temporary table. You can also include your modified column values as well if needed:
select
PrimaryKey,
Col1
--Col2... etc
into #NewRecords
from Table
--where whatever...
Then do your INSERT with the OUTPUT clause to capture your new ids into the table variable:
declare #TableVariable table (
New_ID int not null
);
INSERT INTO #table
(Col1 /*,Col2... ect.*/)
OUTPUT INSERTED.PrimaryKey INTO #NewIds
SELECT Col1 /*,Col2... ect.*/
from #NewRecords
order by PrimaryKey
Because of the ORDER BY PrimaryKey statement, you will be guaranteed that your New_ID numbers will be generated in the same order as the PrimaryKey field of the copied records. Now you can match them up by row numbers ordered by the ID values. The following query would give you the parings:
select PrimaryKey, New_ID
from
(select PrimaryKey,
ROW_NUMBER() over (order by PrimaryKey) OldRow
from #NewRecords
) PrimaryKeys
join
(
select New_ID,
ROW_NUMBER() over (order by New_ID) NewRow
from #NewIds
) New_IDs
on OldRow = NewRow
Is it possible to have a non-primary key to be auto-incremented with every insertion?
For example, I want to have a log, where every log entry has a primary key (for internal use), and a revision number ( a INT value that I want to be auto-incremented).
As a workaround, this could be done with a sequence, yet I believe that sequences are not supported in SQLite.
You can do select max(id)+1 when you do the insertion.
For example:
INSERT INTO Log (id, rev_no, description)
VALUES ((SELECT MAX(id) + 1 FROM log), 'rev_Id', 'some description')
Note that this will fail on an empty table since there won't be a record with id is 0 but you can either add a first dummy entry or change the sql statement to this:
INSERT INTO Log (id, rev_no, description)
VALUES ((SELECT IFNULL(MAX(id), 0) + 1 FROM Log), 'rev_Id', 'some description')
SQLite creates a unique row id (rowid) automatically. This field is usually left out when you use "select * ...", but you can fetch this id by using "select rowid,* ...". Be aware that according to the SQLite documentation, they discourage the use of autoincrement.
create table myTable ( code text, description text );
insert into myTable values ( 'X', 'some descr.' );
select rowid, * from myTable;
:: Result will be;
1|X|some descr.
If you use this id as a foreign key, you can export rowid - AND import the correct value in order to keep data integrity;
insert into myTable values( rowid, code text, description text ) values
( 1894, 'X', 'some descr.' );
You could use a trigger (http://www.sqlite.org/lang_createtrigger.html) that checks the previous highest value and then increments it, or if you are doing your inserts through in a stored procedure, put that same logic in there.
My answer is very similar to Icarus's so I no need to mention it.
You can use Icarus's solution in a more advanced way if needed. Below is an example of seat availiabilty table for a train reservation system.
insert into Availiability (date,trainid,stationid,coach,seatno)
values (
'11-NOV-2013',
12076,
'SRR',
1,
(select max(seatno)+1
from Availiability
where date='11-NOV-2013'
and trainid=12076
and stationid='SRR'
and coach=1)
);
You can use an AFTER INSERT trigger to emulate a sequence in SQLite (but note that numbers might be reused if rows are deleted). This will make your INSERT INTO statement a lot easier.
In the following example, the revision column will be auto-incremented (unless the INSERT INTO statement explicitly provides a value for it, of course):
CREATE TABLE test (
id INTEGER PRIMARY KEY NOT NULL,
revision INTEGER,
description TEXT NOT NULL
);
CREATE TRIGGER auto_increment_trigger
AFTER INSERT ON test
WHEN new.revision IS NULL
BEGIN
UPDATE test
SET revision = (SELECT IFNULL(MAX(revision), 0) + 1 FROM test)
WHERE id = new.id;
END;
Now you can simply insert a new row like this, and the revision column will be auto-incremented:
INSERT INTO test (description) VALUES ('some description');