Related
I've got a table as follows
Table1
ID Name Tag
-----------------
1 N1 2.1
2 N2 3.5
3 N1 3.5
4 N3 8.1
I create a new table Table2 with ID and Name (unique constraint) and I want to insert Table1's contents into Table2 avoiding duplicates, in the sense that I want only 1, 2 and 4 from Table1 in Table2.
I've tried this but it doesn't seem to work and I get the unique constraint error (ORACLE SQL)
INSERT INTO TABLE2 (ID, NAME)
SELECT ID, NAME
FROM TABLE1
WHERE NAME NOT IN (SELECT NAME FROM TABLE2);
Please can someone point me in the right direction?
Sorry for not making myself clear. Table2 is a brand new table. I want the first values inserted, the following duplicates should be ignored. So in my case, N1, N2 get inserted, N1 is dupe so it is ignored, N3 is inserted
OK - from your description, I understand table t2 is currently empty, and you want to copy the rows where id is in (1, 2, 4) from table t1 to table t2.
Why your code fails:
You seem to believe that the condition is applied to the first row in t1, it passes so it is inserted into t2, then the condition is applied to the second row in t1 (using what is already inserted in t2), etc. - and you don't understand why there is any attempt to insert ALL the rows from t1 into t2. Why doesn't the third row fail the WHERE clause?
Good question! The reason is that operations are done on a SET basis. The WHERE condition uses table t2 AS IT WAS before the INSERT operation began. So for ALL rows, the WHERE clause compares to an empty table t2.
How to fix this... Decide which id you want to add when there are duplicate names. For example, one way to get the result you said you wanted is to select MIN(id) for each name. Moreover, you still want to check if the name exists in t2 already (since you may do this again in the future, when t2 is already partially populated).
insert into t2 ( id, name )
select min(id), name
from t1
where name not in (select name from t2)
group by name
;
You can try it bother....!
Insert into tb2(Field1, Field2)
SELECT Field1, Field2
FROM tb1
WHERE NOT EXISTS (SELECT Field1 FROM tb1) ;
This is how I understood the question:
SQL> create table table2
2 (id number,
3 name varchar2(2),
4 tag number,
5 constraint pk_t2 primary key (id, name)
6 );
Table created.
SQL>
SQL> insert into table2 (id, name, tag)
2 with test (id, name, tag) as
3 (select 1, 'N1', 2.1 from dual union
4 select 2, 'N2', 3.5 from dual union
5 select 3, 'N1', 3.5 from dual union
6 select 4, 'N3', 8.1 from dual
7 )
8 select min(id), name, max(tag)
9 from test
10 group by name;
3 rows created.
SQL>
SQL> select * from table2 order by id;
ID NA TAG
---------- -- ----------
1 N1 3,5
2 N2 3,5
4 N3 8,1
SQL>
When we need to unique any two or more column we have to create unique index.
Run this query
ALTER TABLE TABLE2 ADD UNIQUE unique_index( id, name);
and then
INSERT INTO TABLE2 (id,name,tag) VALUES(1, "N1", 3.5 )
ON DUPLICATE KEY UPDATE tag=3.5
this will also help to update new tag
Try to check if the id and name from Table1 is doesn't exist in Table2, if then insert.
If the unique constraint on TABLE2 is a composite key then run this:
INSERT INTO TABLE2 (ID, NAME)
SELECT A.ID, A.NAME
FROM TABLE1 A
WHERE NOT EXISTS (SELECT NULL FROM TABLE2 B WHERE A.ID=B.ID AND A.NAME=B.NAME);
If there are two unique constraints; one on the id, and the other on the name then run this instead:
INSERT INTO TABLE2 (ID, NAME)
SELECT A.ID, A.NAME
FROM TABLE1 A
WHERE NOT EXISTS (SELECT NULL FROM TABLE2 B WHERE A.ID=B.ID OR A.NAME=B.NAME);
ORACLE, in case you need to get values from 2 different tables.
below example,i use an increment case.
INSERT INTO TABLE1
(INDEX, REMARKS, NAME, AGE)
(SELECT (SELECT colescs(MAX(INDEX),0) FROM TABLE1)+1,
'any remarks',
t2.NAME, t2,age from TABLE2 t2 where t2.name = 'apple')
explanation
match below numbers (1)-(1), (2)-(2) ...
INSERT INTO TABLE1
(INDEX, //index increment (1)
REMARKS, //hard code (2)
NAME, //from table2 (3)
AGE) //from table2 (4)
(SELECT // this part is to get values from another table
(SELECT colescs(MAX(INDEX),0) FROM TABLE1)+1, //increment (1)
'any remarks', //hard code value (2)
t2.NAME, //from table2 (3)
t2,age //from table2 (4)
from TABLE2 t2 where t2.name = 'apple') //condition for table2
I'm looking for a good SQL approach (Oracle database) to fulfill the next requirements:
Delete rows from Table A that are not present in Table B.
Both tables have identical structure
Some fields are nullable
Amount of columns and rows is huge (more 100k rows and 20-30 columns to compare)
Every single field of every single row needs to be compared from Table A against table B.
Such requirement is owing to a process that must run every day as changes will come from Table B.
In other words: Table A Minus Table B => Delete the records from the Table A
delete from Table A
where (field1, field2, field3) in
(select field1, field2, field3
from Table A
minus
select field1, field2, field3
from Table B);
It's very important to mention that a normal MINUS within DELETE clause fails as does not take the nulls on nullable fields into consideration (unknown result for oracle, then no match).
I also tried EXISTS with success, but I have to use NVL function to replace the nulls with dummy values, which I don't want it as I cannot guarantee that the value replaced in NVL will not come as a valid value in the field.
Does anybody know a way to accomplish such thing? Please remember performance and nullable fields as "a must".
Thanks ever
decode finds sameness (even if both values are null):
decode( field1, field2, 1, 0 ) = 1
To delete rows in table1 not found in table2:
delete table1 t
where t.rowid in (select t1.rowid
from table1 t1
left outer join table2 t2
on decode(t1.field1, t2.field1, 1, 0) = 1
and decode(t1.field2, t2.field2, 1, 0) = 1
and decode(t1.field3, t2.field3, 1, 0) = 1
/* ... */
where t2.rowid is null /* no matching row found */
)
to use existing indexes
...
left outer join table2 t2
on (t1.index_field1=t2.index_field1 or
t1.index_field1 is null and t2.index_field1 is null)
and ...
Use a left outer join and test for null in your where clause
delete a
from a
left outer join b on a.x = b.x
where b.x is null
Have you considered ORALCE SQL MERGE statement?
Use Bulk operation for huge number of records. Performance wise it will be faster.
And use join between two table to get rows to be delete. Nullable columns can be compared with some default value.
Also, if you want Table A to be similar as Table B, why don't you truncate table A and then insert data from table b
Assuming you the same PK field available on each table...(Having a PK or some other unique key is critical for this.)
create table table_a (id number, name varchar2(25), dob date);
insert into table_a values (1, 'bob', to_date('01-01-1978','MM-DD-YYYY'));
insert into table_a values (2, 'steve', null);
insert into table_a values (3, 'joe', to_date('05-22-1989','MM-DD-YYYY'));
insert into table_a values (4, null, null);
insert into table_a values (5, 'susan', to_date('08-08-2005','MM-DD-YYYY'));
insert into table_a values (6, 'juan', to_date('11-17-2001', 'MM-DD-YYYY'));
create table table_b (id number, name varchar2(25), dob date);
insert into table_b values (1, 'bob', to_date('01-01-1978','MM-DD-YYYY'));
insert into table_b values (2, 'steve',to_date('10-14-1992','MM-DD-YYYY'));
insert into table_b values (3, null, to_date('05-22-1989','MM-DD-YYYY'));
insert into table_b values (4, 'mary', to_date('12-08-2012','MM-DD-YYYY'));
insert into table_b values (5, null, null);
commit;
-- confirm minus is working
select id, name, dob
from table_a
minus
select id, name, dob
from table_b;
-- from the minus, re-query to just get the key, then delete by key
delete table_a where id in (
select id from (
select id, name, dob
from table_a
minus
select id, name, dob
from table_b)
);
commit;
select * from table_a;
But, if at some point in time, tableA is to be reset to the same as tableB, why not, as another answer suggested, truncate tableA and select all from tableB.
100K is not huge. I can do ~100K truncate and insert on my laptop instance in less than 1 second.
> DELETE FROM purchase WHERE clientcode NOT IN (
> SELECT clientcode FROM client );
This deletes the rows from the purchase table whose clientcode are not in the client table. The clientcode of purchase table references the clientcode of client table.
DELETE FROM TABLE1 WHERE FIELD1 NOT IN (SELECT CLIENT1 FROM TABLE2);
I want to write a query which finds the difference between two tables and writes updates or new data into third table. My two tables have identical column names. Third table which captures changes have extra column called comment. I would like to insert the comment whether it is a new row or updated row based on the row modification.
**TABLE1 (BACKUP)**
KEY,FIRST_NAME,LAST_NAME,CITY
1,RAM,KUMAR,INDIA
2,TOM,MOODY,ENGLAND
3,MOHAMMAD,HAFEEZ,PAKISTAN
4,MONIKA,SAM,USA
5,MIKE,PALEDINO,USA
**TABLE2 (CURRENT)**
KEY,FIRST_NAME,LAST_NAME,CITY
1,RAM,KUMAR,USA
2,TOM,MOODY,ENGLAND
3,MOHAMMAD,HAFEEZ,PAKISTAN
4,MONIKA,SAM,INDIA
5,MIKE,PALEDINO,USA
6,MAHELA,JAYA,SL
**TABLE3 (DIFFERENCE FROM TABLE2 TO TABLE1)**
KEY,FIRST_NAME,LAST_NAME,CITY,COMMENT
1,RAM,KUMAR,USA,UPDATE
4,MONIKA,SAM,INDIA,UPDATE
6,MAHELA,JAYA,SL,INSERT
table scripts
DROP TABLE TABLE1;
DROP TABLE TABLE2;
DROP TABLE TABLE3;
CREATE TABLE TABLE1
(
KEY NUMBER,
FIRST_NAME VARCHAR2(100),
LAST_NAME VARCHAR2(100),
CITY VARCHAR2(50)
);
/
CREATE TABLE TABLE2
(
KEY NUMBER,
FIRST_NAME VARCHAR2(100),
LAST_NAME VARCHAR2(100),
CITY VARCHAR2(50)
);
/
CREATE TABLE TABLE3
(
KEY NUMBER,
FIRST_NAME VARCHAR2(100),
LAST_NAME VARCHAR2(100),
CITY VARCHAR2(50),
COMMENTS VARCHAR2(200)
);
/
INSERT ALL
INTO TABLE1
VALUES(1,'RAM','KUMAR','INDIA')
INTO TABLE1 VALUES(2,'TOM','MOODY','ENGLAND')
INTO TABLE1 VALUES(3,'MOHAMMAD','HAFEEZ','PAKISTAN')
INTO TABLE1 VALUES(4,'MONIKA','SAM','USA')
INTO TABLE1 VALUES(5,'MIKE','PALEDINO','USA')
SELECT 1 FROM DUAL;
/
INSERT ALL
INTO TABLE2
VALUES(1,'RAM','KUMAR','USA')
INTO TABLE2 VALUES(2,'TOM','MOODY','ENGLAND')
INTO TABLE2 VALUES(3,'MOHAMMAD','HAFEEZ','PAKISTAN')
INTO TABLE2 VALUES(4,'MONIKA','SAM','INDIA')
INTO TABLE2 VALUES(5,'MIKE','PALEDINO','USA')
INTO TABLE2 VALUES(6,'MAHELA','JAYA','SL')
SELECT 1 FROM DUAL;
I was using the merge statement to accomplish the same. but i have hit a roadblock in merge statement , it's rhrowing an error "SQL Error: ORA-00905: missing keyword
00905. 00000 - "missing keyword"" I dont understand where is the error. please help
INSERT INTO TABLE3
SELECT KEY,FIRST_NAME,LAST_NAME,CITY,NULL AS COMMENTS FROM TABLE2
MINUS
SELECT KEY,FIRST_NAME,LAST_NAME,CITY,NULL AS COMMENTS FROM TABLE1
;
MERGE INTO TABLE3 A
USING TABLE1 B
ON (A.KEY=B.KEY)
WHEN MATCHED THEN
UPDATE SET A.COMMENTS='UPDATED'
WHEN NOT MATCHED THEN
UPDATE SET A.COMMENTS='INSERTED';
There is no such WHEN NOT MATCHED THEN UPDATE clause, you should use WHEN NOT MATCHED THEN INSERT. Refer to MERGE for details.
A few assumptions made about the data:
An INSERT event will be a record identified by its key in table2 (current data) that does not have a matching key in the original back-up table: table1.
An UPDATE event is a field that exists in both table1 and table2 for the same KEY but is not the same.
Records which did not change between tables are not to be recorded in table3.
Example Query: Check for Updates
SELECT UPD_QUERY.NEW_CITY, 'UPDATED' as COMMENTS
FROM (SELECT CASE WHEN REPLACE(CURR.CITY, BKUP.CITY,'') IS NOT NULL THEN CURR.CITY
ELSE NULL END as NEW_CITY
FROM table1 BKUP, table2 CURR
WHERE BKUP.KEY = CURR.KEY) UPD_QUERY
WHERE UPD_QUERY.NEW_CITY is NOT NULL;
You can repeat this comparison method for the other fields:
SELECT UPD_QUERY.*
FROM (SELECT CURR.KEY,
CASE WHEN REPLACE(CURR.FIRST_NAME, BKUP.FIRST_NAME,'') IS NOT NULL
THEN CURR.FIRST_NAME
ELSE NULL END as FIRST_NAME,
CASE WHEN REPLACE(CURR.LAST_NAME, BKUP.LAST_NAME,'') IS NOT NULL
THEN CURR.LAST_NAME
ELSE NULL END as LAST_NAME,
CASE WHEN REPLACE(CURR.CITY, BKUP.CITY,'') IS NOT NULL
THEN CURR.CITY
ELSE NULL END as CITY
FROM table1 BKUP, table2 CURR
WHERE BKUP.KEY = CURR.KEY) UPD_QUERY
WHERE COALESCE(UPD_QUERY.FIRST_NAME, UPD_QUERY.LAST_NAME, UPD_QUERY.CITY)
is NOT NULL;
NOTE: This could get unwieldy very quickly if the number of columns compared are many. Since the target table design (table3) requires not only identification of a change, but the field and its new value are also recorded.
Example Query: Look for Newly Added Records
SELECT CURR.*, 'INSERTED' as COMMENTS
FROM table2 CURR, table1 BKUP
WHERE CURR.KEY = BKUP.KEY(+)
AND BKUP.KEY is NULL;
Basically MERGE forces the operation: MATCHED=UPDATE (or DELETE), NOT MATCHED = INSERT. It's in the docs.
You can do what you want but you need two insert statements with different set operators,
For UPDATED:
Insert into table3
table1 INTERSECT table2
For INSERTED:
Insert into table3
table2 MINUS table1
I need to update a query so that it checks that a duplicate entry does not exist before insertion. In MySQL I can just use INSERT IGNORE so that if a duplicate record is found it just skips the insert, but I can't seem to find an equivalent option for Oracle. Any suggestions?
If you're on 11g you can use the hint IGNORE_ROW_ON_DUPKEY_INDEX:
SQL> create table my_table(a number, constraint my_table_pk primary key (a));
Table created.
SQL> insert /*+ ignore_row_on_dupkey_index(my_table, my_table_pk) */
2 into my_table
3 select 1 from dual
4 union all
5 select 1 from dual;
1 row created.
Check out the MERGE statement. This should do what you want - it's the WHEN NOT MATCHED clause that will do this.
Do to Oracle's lack of support for a true VALUES() clause the syntax for a single record with fixed values is pretty clumsy though:
MERGE INTO your_table yt
USING (
SELECT 42 as the_pk_value,
'some_value' as some_column
FROM dual
) t on (yt.pk = t.the_pke_value)
WHEN NOT MATCHED THEN
INSERT (pk, the_column)
VALUES (t.the_pk_value, t.some_column);
A different approach (if you are e.g. doing bulk loading from a different table) is to use the "Error logging" facility of Oracle. The statement would look like this:
INSERT INTO your_table (col1, col2, col3)
SELECT c1, c2, c3
FROM staging_table
LOG ERRORS INTO errlog ('some comment') REJECT LIMIT UNLIMITED;
Afterwards all rows that would have thrown an error are available in the table errlog. You need to create that errlog table (or whatever name you choose) manually before running the insert using DBMS_ERRLOG.CREATE_ERROR_LOG.
See the manual for details
I don't think there is but to save time you can attempt the insert and ignore the inevitable error:
begin
insert into table_a( col1, col2, col3 )
values ( 1, 2, 3 );
exception when dup_val_on_index then
null;
end;
/
This will only ignore exceptions raised specifically by duplicate primary key or unique key constraints; everything else will be raised as normal.
If you don't want to do this then you have to select from the table first, which isn't really that efficient.
Another variant
Insert into my_table (student_id, group_id)
select distinct p.studentid, g.groupid
from person p, group g
where NOT EXISTS (select 1
from my_table a
where a.student_id = p.studentid
and a.group_id = g.groupid)
or you could do
Insert into my_table (student_id, group_id)
select distinct p.studentid, g.groupid
from person p, group g
MINUS
select student_id, group_id
from my_table
A simple solution
insert into t1
select from t2
where not exists
(select 1 from t1 where t1.id= t2.id)
This one isn't mine, but came in really handy when using sqlloader:
create a view that points to your table:
CREATE OR REPLACE VIEW test_view
AS SELECT * FROM test_tab
create the trigger:
CREATE OR REPLACE TRIGGER test_trig
INSTEAD OF INSERT ON test_view
FOR EACH ROW
BEGIN
INSERT INTO test_tab VALUES
(:NEW.id, :NEW.name);
EXCEPTION
WHEN DUP_VAL_ON_INDEX THEN NULL;
END test_trig;
and in the ctl file, insert into the view instead:
OPTIONS(ERRORS=0)
LOAD DATA
INFILE 'file_with_duplicates.csv'
INTO TABLE test_view
FIELDS TERMINATED BY ','
(id, field1)
How about simply adding an index with whatever fields you need to check for dupes on and say it must be unique? Saves a read check.
yet another "where not exists"-variant using dual...
insert into t1(id, unique_name)
select t1_seq.nextval, 'Franz-Xaver' from dual
where not exists (select 1 from t1 where unique_name = 'Franz-Xaver');
I have 2 tables - A and B . Table A has two columns, pkey (primary key) and col1. Table B also has two columns, pr_key (primary key but not a foreign key) and column1. Both tables have 4 rows. Table B has no values in column1, while table A has column1 values for all 4 rows. So my data looks like this
Table A
pkey col1
A 10
B 20
C 30
D 40
Table B
pr_key column1
A null
B null
C null
D null
I want to update table B to set the column1 value of each row equal to the column1 value of the equivalent row from table A in a single DML statement.
Should be something like that (depends on SQL implementation you use, but in general, the following is rather standard. In particular should work in MS-SQL and in MySQL.
INSERT INTO tblB (pr_key, column1)
SELECT pkey, col1
FROM tblA
-- WHERE some condition (if you don't want 100% of A to be copied)
The question is a bit unclear as to the nature of tblB's pr_key, if for some reason this was a default/auto-incremented key for that table, it could just then be omitted from both the column list (in parenthesis) and in the SELECT that follows. In this fashion upon insertion of each new row, a new value would be generated.
Edit: It appears the OP actually wants to update table B with values from A.
The syntax for this should then be something like
UPDATE tblB
SET Column1 = A.Col1
FROM tblA AS A
JOIN tblB AS B ON B.pr_key = A.pkey
This may perform better:
MERGE INTO tableB
USING (select pkey, col1 from tableA) a
ON (tableB.pr_key = a.pkey)
WHEN MATCHED THEN UPDATE
SET tableB.column1 = a.col1;
It sounds like you want to do a correlated update. The syntax for that in Oracle is
UPDATE tableB b
SET column1 = (SELECT a.column1
FROM tableA a
WHERE a.pkey = b.pr_key)
WHERE EXISTS( SELECT 1
FROM tableA a
WHERE a.pkey = b.pr_key )
The WHERE EXISTS clause isn't necessary if tableA and tableB each have 4 rows and have the same set of keys in each. It is much safer to include that option, though, to avoid updating column1 values of tableB to NULL if there is no matching row in tableA.