How to only delete data using merge using oracle...
I am using the below code:
Merge
into
target_table
using
source_tablle
on (...)
when matched
then delete
But I am getting an error "missing Keyword" at last line
Your MERGE at the end is missing the UPDATE clause.
Lets look at a sample MERGE
CREATE TABLE employee (
employee_id NUMBER(5),
first_name VARCHAR2(20),
last_name VARCHAR2(20),
dept_no NUMBER(2),
salary NUMBER(10));
INSERT INTO employee VALUES (1, 'Dan', 'Morgan', 10, 100000);
INSERT INTO employee VALUES (2, 'Helen', 'Lofstrom', 20, 100000);
INSERT INTO employee VALUES (3, 'Akiko', 'Toyota', 20, 50000);
INSERT INTO employee VALUES (4, 'Jackie', 'Stough', 20, 40000);
INSERT INTO employee VALUES (5, 'Richard', 'Foote', 20, 70000);
INSERT INTO employee VALUES (6, 'Joe', 'Johnson', 20, 30000);
INSERT INTO employee VALUES (7, 'Clark', 'Urling', 20, 90000);
CREATE TABLE bonuses (
employee_id NUMBER, bonus NUMBER DEFAULT 100);
INSERT INTO bonuses (employee_id) VALUES (1);
INSERT INTO bonuses (employee_id) VALUES (2);
INSERT INTO bonuses (employee_id) VALUES (4);
INSERT INTO bonuses (employee_id) VALUES (6);
INSERT INTO bonuses (employee_id) VALUES (7);
COMMIT;
Now we have a sample data structure lets do some merging:
MERGE INTO bonuses b
USING (
SELECT employee_id, salary, dept_no
FROM employee
WHERE dept_no =20) e
ON (b.employee_id = e.employee_id)
WHEN MATCHED THEN
UPDATE SET b.bonus = e.salary * 0.1
DELETE WHERE (e.salary < 40000)
;
So this command the MERGE syntax using the merge_update_clause:
MERGE INTO (table/view)
USING (table/view)
ON (condition)
WHEN MATCHED THEN
UPDATE SET (column..expression)
DELETE WHERE (condition)
I guess what I'm hinting at is that you are missing your UPDATE SET clause as well as the DELETE conditions. I recommend following up on the MERGE syntax.
**Edit:**SQLFiddle is back so here you go.
Related
sample data I have 2 columns old_store_id, changed_new_store_id and there are cases when changed_new_store_id value will also get updated to new value. how can i traverse through DB(teradata) to get the last value (changed_new_store_id ) of the respective old_store_id
let say in 1 st row
old_store_id = A ;
changed_new_store_id = B
and 5 th row contains
old_store_id = B ;
changed_new_store_id = C
and some other nth row C is changed to X etc
how to get final value of A which is X ?
I can try using multiple self joins
using Stored procedure but it will not be an efficient way (for many reasons)
Is there any way to find ?
Please anyone suggest me
This assumes no "loops", and uses "bottom-up" recursion. Something very similar could be done "top-down", limiting the seed query to rows where the "old" value doesn't appear anywhere as a "new" value.
CREATE VOLATILE TABLE #Example (
Old_Store_ID VARCHAR(8),
New_Store_ID VARCHAR(8)
)
PRIMARY INDEX(Old_Store_ID)
ON COMMIT PRESERVE ROWS;
INSERT INTO #Example VALUES ('A', 'B');
INSERT INTO #Example VALUES ('D', 'c');
INSERT INTO #Example VALUES ('B', 'F');
INSERT INTO #Example VALUES ('c', 'FF');
INSERT INTO #Example VALUES ('FF', 'GG');
INSERT INTO #Example VALUES ('F', 'X');
WITH RECURSIVE #Traverse(Old_Store_ID,New_Store_ID,Final_ID)
AS
(
--Seed Query - start with only the rows having no further changes
SELECT Old_Store_ID
,New_Store_ID
,New_Store_ID as Final_ID
FROM #Example as This
WHERE NOT EXISTS (
SELECT 1 FROM #Example AS Other WHERE This.New_Store_ID = Other.Old_Store_ID
)
UNION ALL
--Recursive Join
SELECT NewRow.Old_Store_ID
,NewRow.New_Store_ID
,OldRow.Final_ID
FROM #Example AS NewRow
INNER JOIN #Traverse AS OldRow
ON NewRow.New_Store_ID = OldRow.Old_Store_ID
)
SELECT *
FROM #Traverse
;
A recursive answer:
CREATE VOLATILE TABLE #SearchList (
SearchID CHAR(2),
ParentSearchID CHAR(2)
)
PRIMARY INDEX(SearchID)
ON COMMIT PRESERVE ROWS;
INSERT INTO #SearchList VALUES ('A', 'B');
INSERT INTO #SearchList VALUES ('D', 'c');
INSERT INTO #SearchList VALUES ('B', 'F');
INSERT INTO #SearchList VALUES ('c', 'FF');
INSERT INTO #SearchList VALUES ('FF', 'GG');
INSERT INTO #SearchList VALUES ('F', 'X');
CREATE VOLATILE TABLE #IntermediateResults(
SearchID CHAR(2),
ParentSearchID CHAR(2),
SearchLevel INTEGER
)
ON COMMIT PRESERVE ROWS;
INSERT INTO #IntermediateResults
WITH RECURSIVE RecursiveParent(SearchID,ParentSearchID,SearchLevel)
AS
(
--Seed Query
SELECT SearchID
,ParentSearchID
,1
FROM #SearchList
UNION ALL
--Recursive Join
SELECT a.SearchID
,b.ParentSearchID
,SearchLevel+1
FROM #SearchList a
INNER JOIN RecursiveParent b
ON a.ParentSearchID = b.SearchID
)
SELECT SearchID
,ParentSearchID
,MAX(SearchLevel)
FROM RecursiveParent
GROUP BY SearchID
,ParentSearchID
;
SELECT RESULTS.*
FROM #IntermediateResults RESULTS
INNER JOIN (SELECT RESULTS_MAX.SearchID
,MAX(RESULTS_MAX.SearchLevel) MaxSearchLevel
FROM #IntermediateResults RESULTS_MAX
GROUP BY RESULTS_MAX.SearchID
) GROUPED_RESULTS
ON RESULTS.SearchID = GROUPED_RESULTS.SearchID
AND RESULTS.SearchLevel = GROUPED_RESULTS.MaxSearchLevel
ORDER BY RESULTS.SearchID ASC
,RESULTS.SearchLevel ASC
;
Output:
SearchID ParentSearchID SearchLevel
-------- -------------- -----------
A X 3
B X 2
c GG 2
D GG 3
F X 1
FF GG 1
In two columns within the same table (idParent1 and idParent2), I want to know if there are any two equal ids in any row (not just in the same row). If there are equal values (in any row) I want to obtain these ids.
I try this without success.
SELECT idParent1
FROM
Person
WHERE
Person.idParent1 IN Person.idParent2;
I'm getting the error: no such table: Person.idParent2
Example:
sqlite> CREATE TABLE Person(
ID INT PRIMARY KEY NOT NULL,
Parent1 INT NOT NULL,
Parent2 INT NOT NULL,
);
INSERT INTO Person (ID,Parent1,Parent2)
VALUES (1, 2,3);
INSERT INTO Person (ID,Parent1,Parent2)
VALUES (2, 5,6);
INSERT INTO Person (ID,Parent1,Parent2)
VALUES (3, 7,5);
INSERT INTO Person (ID,Parent1,Parent2)
VALUES (9, 10,12);
INSERT INTO Person (ID,Parent1,Parent2)
VALUES (45, 2,3);
In this example 5 is common in Parent1 and Parent2. I want to identify all the values like 5 are present in both columns
If you want to check only for idParent1:
SELECT idParent1
FROM
Person
WHERE
Person.idParent1 IN (
SELECT
idParent2
FROM
Person
);
or
SELECT idParent1
FROM
Person AS p
WHERE EXISTS (SELECT 1 FROM Person WHERE Person.idParent2 = p.idParent1);
A similar solution can apply to idParent2.
Your syntax is not correct. The correct syntax is:
SELECT idParent1 FROM Person WHERE idParent1 IN (SELECT idParent2 FROM Person)
I've been spoiled by years of PostgreSQL and am having a hard time adapting to sqlite's limited update syntax. I cobbled together a working query, but I'm hoping someone might know of a better way. (This isn't very pretty to look at and is the product of sqlite guiding me with error messages).
Scenario:
I have a standard association table setup: A, A2B, B
I want to update every record in A with the "latest" corresponding B (B is joined through the A2B association table, and the "latest" is a max function on a B column).
-- works
UPDATE t_a
SET id_latest_b = (
SELECT id_b FROM (
SELECT t_b.id as id_b,
max(t_b.timestamp_event),
t_a2b.id_a
FROM t_b
JOIN t_a2b
ON (t_b.id = t_a2b.id_b)
GROUP BY t_a2b.id_a
) q_inner
WHERE
t_a.id = q_inner.id_a
);
-- test data
CREATE TABLE t_b (id INT PRIMARY KEY, timestamp_event INT);
CREATE TABLE t_a (id INT PRIMARY KEY, id_latest_b INT REFERENCES t_b(id));
CREATE TABLE t_a2b (id_a REFERENCES t_a(id), id_b REFERENCES t_b(id), PRIMARY KEY (id_a, id_b));
INSERT INTO t_a VALUES (1, NULL);
INSERT INTO t_a VALUES (2, NULL);
INSERT INTO t_a VALUES (3, NULL);
INSERT INTO t_a VALUES (4, NULL);
INSERT INTO t_b VALUES (1, 10);
INSERT INTO t_b VALUES (2, 20);
INSERT INTO t_b VALUES (3, 30);
INSERT INTO t_a2b VALUES (1, 1);
INSERT INTO t_a2b VALUES (1, 2);
INSERT INTO t_a2b VALUES (2, 2);
INSERT INTO t_a2b VALUES (3, 1);
INSERT INTO t_a2b VALUES (3, 2);
INSERT INTO t_a2b VALUES (3, 3);
INSERT INTO t_a2b VALUES (4, 1);
INSERT INTO t_a2b VALUES (4, 4);
You can use ORDER BY to get the row with the largest value:
UPDATE t_a
SET id_latest_b = (SELECT t_b.id
FROM t_b
JOIN t_a2b ON t_b.id = t_a2b.id_b
WHERE t_a2b.id_a = t_a.id
ORDER BY t_b.timestamp_event DESC
LIMIT 1);
I've got two tables already populated with data with the given schemas:
CREATE TABLE objects
(
id BIGINT NOT NULL,
latitude BIGINT NOT NULL,
longitude BIGINT NOT NULL,
PRIMARY KEY (id)
)
CREATE TABLE tags
(
id BIGINT NOT NULL,
tag_key VARCHAR(100) NOT NULL,
tag_value VARCHAR(500),
PRIMARY KEY (id , tag_key)
)
object.id and tags.id refer to the same object
I'd like to populate a third table with the unique combinations of tag_key and tag_value. For example:
INSERT OR REPLACE INTO objects (id) VALUES (0);
INSERT OR REPLACE INTO tags (id, tag_key, tag_value) VALUES (0, 'a', 'x');
INSERT OR REPLACE INTO objects (id) VALUES (1);
INSERT OR REPLACE INTO tags (id, tag_key, tag_value) VALUES (1, 'a', 'y');
INSERT OR REPLACE INTO objects (id) VALUES (2);
INSERT OR REPLACE INTO tags (id, tag_key, tag_value) VALUES (2, 'a', 'x');
INSERT OR REPLACE INTO tags (id, tag_key, tag_value) VALUES (2, 'a', 'y');
INSERT OR REPLACE INTO objects (id) VALUES (3);
INSERT OR REPLACE INTO tags (id, tag_key, tag_value) VALUES (3, 'a', 'x');
INSERT OR REPLACE INTO objects (id) VALUES (4);
INSERT OR REPLACE INTO tags (id, tag_key, tag_value) VALUES (4, 'a', 'y');
Should result in 3 entries of
0: ([a,x])
1: ([a,y])
3: ([a,x][a,y])
Currently I have:
CREATE TABLE tags_combinations
(
id INTEGER PRIMARY KEY,
tag_key VARCHAR(100) NOT NULL,
tag_value VARCHAR(500)
);
The id shouldn't be related to the original id of the object, just something to group unique combinations.
This is the query I have so far:
SELECT
t1.tag_key, t1.tag_value
FROM
tags t1
WHERE
t1.id
IN
(
/* select ids who's every tags entry is not under one id in tags_combinations */
SELECT
t2.id
FROM
tags t2
WHERE
t2.tag_key, t2.tag_value
NOT IN
(
)
);
The part with the comment is what I am not sure about, how would I select every id from tags that does not have all of the corresponding tag_key and tag_value entries already under one id in tags_combinations?
To clarify exactly the result I am after: From the sample data given, it should return 4 rows with:
row id tag_key tag_value
0 0 a x
1 1 a y
2 2 a x
3 2 a y
SQL is a set-based language. If you reformulate your question in the language of set theory, you can directly translate it into SQL:
You want all rows of the tags table, except those from duplicate objects.
Objects are duplicates if they have exactly the same key/value combinations. However, we still want to return one of those objects, so we define duplicates only as those objects where no other duplicate object with a smaller ID exists.
Two objects A and B have exactly the same key/value combinations if
all key/value combinations in A also exist in B, and
all key/value combinations in B also exist in A.
All key/value combinations in A also exist in B if there is no key/value combination in A that does not exist in B (note: double negation).
SELECT id, tag_key, tag_value
FROM tags
WHERE NOT EXISTS (SELECT 1
FROM tags AS dup
WHERE dup.id < tags.id
AND NOT EXISTS (SELECT 1
FROM tags AS A
WHERE A.id = tags.id
AND NOT EXISTS (SELECT 1
FROM tags AS B
WHERE B.id = dup.id
AND B.tag_key = A.tag_key
AND B.tag_value = A.tag_value)
)
AND NOT EXISTS (SELECT 1
FROM tags AS B
WHERE B.id = dup.id
AND NOT EXISTS (SELECT 1
FROM tags AS A
WHERE A.id = tags.id
AND A.tag_key = B.tag_key
AND A.tag_value = B.tag_value)
)
)
ORDER BY id, tag_key;
This is not easy in SQLite. We want to identify groups of tag key/value pairs. So we could group by id and get a string of the associated pairs with group_concat. This would be the way to do it in another DBMS. SQLite, however, cannot order in group_concat, so we might end up with 2: 'a/x,a/y' and 5: 'a/y,a/x'. Two different strings for the same pairs.
Your best bet may be to write a program and find the distinct pairs iteratively.
In SQLite you may want to try this:
insert into tags_combinations (id, tag_key, tag_value)
select id, tag_key, tag_value
from tags
where id in
(
select min(id)
from
(
select id, group_concat(tag_key || '/' || tag_value) as tag_pairs
from
(
select id, tag_key, tag_value
from tags
order by id, tag_key, tag_value
) ordered_data
group by id
) aggregated_data
group by tag_pairs
);
Ordering the data before applying group_concat is likely to get the tag pairs ordered, but in no way guaranteed! If this is something you want to do only once, it may be worth a try, though.
To merge multiple rows into one value, you need a function like group_concat().
The ORDER BY is needed to ensure a consistent order of the rows within a group:
SELECT DISTINCT group_concat(tag_key) AS tag_keys,
group_concat(tag_value) AS tag_values
FROM (SELECT id,
tag_key,
tag_value
FROM tags
ORDER BY id,
tag_key,
tag_value)
GROUP BY id;
If you want to have keys and values interleaved, as shown in the question, you need to do more string concatenation:
SELECT DISTINCT group_concat(tag_key || ',' || tag_value, ';') AS keys_and_values
FROM (...
I can not figure out how to query a SQLite.
needed:
1) Replace the record (the primary key), if the condition (comparison of new and old fields entries)
2) Insert an entry if no such entry exists in the database on the primary key.
Importantly, it has to work very fast!
I can not come up with an effective inquiry.
Edit.
MyInsertRequest - the desired expression.
Script:
CREATE TABLE testtable (a INT PRIMARY KEY, b INT, c INT)
INSERT INTO testtable VALUES (1, 2, 3)
select * from testtable
1|2|3
-- Adds an entry, because the primary key is not
++ MyInsertRequest VALUES (2, 2, 3) {if c>4 then replace}
select * from testtable
1|2|3
2|2|3
-- Adds
++ MyInsertRequest VALUES (3, 8, 3) {if c>4 then replace}
select * from testtable
1|2|3
2|2|3
3|8|3
-- Does nothing, because such a record (from primary key field 'a')
-- is in the database and none c>4
++ MyInsertRequest VALUES (1, 2, 3) {if c>4 then replace}
select * from testtable
1|2|3
2|2|3
3|8|3
-- Does nothing
++ MyInsertRequest VALUES (3, 34, 3) {if c>4 then replace}
select * from testtable
1|2|3
2|2|3
3|8|3
-- replace, because such a record (from primary key field 'a')
-- is in the database and c>2
++ MyInsertRequest VALUES (3, 34, 1) {if c>2 then replace}
select * from testtable
1|2|3
2|2|3
3|34|1
Isn't INSERT OR REPLACE what you need ? e.g. :
INSERT OR REPLACE INTO table (cola, colb) values (valuea, valueb)
When a UNIQUE constraint violation occurs, the REPLACE algorithm
deletes pre-existing rows that are causing the constraint violation
prior to inserting or updating the current row and the command
continues executing normally.
You have to put the condition in a unique constraint on the table. It will automatically create an index to make the check efficient.
e.g.
-- here the condition is on columnA, columnB
CREATE TABLE sometable (columnPK INT PRIMARY KEY,
columnA INT,
columnB INT,
columnC INT,
CONSTRAINT constname UNIQUE (columnA, columnB)
)
INSERT INTO sometable VALUES (1, 1, 1, 0);
INSERT INTO sometable VALUES (2, 1, 2, 0);
select * from sometable
1|1|1|0
2|1|2|0
-- insert a line with a new PK, but with existing values for (columnA, columnB)
-- the line with PK 2 will be replaced
INSERT OR REPLACE INTO sometable VALUES (12, 1, 2, 6)
select * from sometable
1|1|1|0
12|1|2|6
Assuming your requirements are:
Insert a new row when a doesn't exists;
Replacing row when a exist and existing c greater then new c;
Do nothing when a exist and existing c lesser or equal then new c;
INSERT OR REPLACE fits first two requirements.
For last requirement, the only way I know to make an INSERT ineffective is supplying a empty rowset.
A SQLite command like following whould make the job:
INSERT OR REPLACE INTO sometable SELECT newdata.* FROM
(SELECT 3 AS a, 2 AS b, 1 AS c) AS newdata
LEFT JOIN sometable ON newdata.a=sometable.a
WHERE newdata.c<sometable.c OR sometable.a IS NULL;
New data (3,2,1 in this example) is LEFT JOINen with current table data.
Then WHERE will "de-select" the row when new c is not less then existing c, keeping it when row is new, ie, sometable.* IS NULL.
I tried the others answers because I was also suffering from a solution to this problem.
This should work, however I am unsure about the performance implications. I believe that you may need the first column to be unique as a primary key else it will simply insert a new record each time.
INSERT OR REPLACE INTO sometable
SELECT columnA, columnB, columnC FROM (
SELECT columnA, columnB, columnC, 1 AS tmp FROM sometable
WHERE sometable.columnA = 1 AND
sometable.columnB > 9
UNION
SELECT 1 AS columnA, 1 As columnB, 404 as columnC, 0 AS tmp)
ORDER BY tmp DESC
LIMIT 1
In this case one dummy query is executed and union-ed onto a second query which would have a performance impact depending on how it is written and how the table is indexed. The next performance problem has potential where the results are ordered and limited. However, I expect that the second query should only return one record and therefore it should not be too much of a performance hit.
You can also omit the ORDER BY tmp LIMIT 1 and it works with my version of sqlite, but it may impact performance since it can end up updating the record twice (writing the original value then the new value if applicable).
The other problem is that you end up with a write to the table even if the condition states that it should not be updated.