Message ID: Hello, I want to update my database if the key value is already there then it will update the required field else it will insert the new row in the same table. Insert query works fine but I am not able to figure out how to achieve this 'IF EXISTS then UPDATE else INSERT' using a one liner MYSQL statement. If someone can give me an example to write such query and execute it from perl then it would be really appreciated. Pratap. PERL MYSQL query 'IF EXISTS then UPDATE else INSERT' by S Pratap Singh.

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ON DUPLICATE KEY UPDATE Syntax If you specify an ON DUPLICATE KEY UPDATE clause and a row to be inserted would cause a duplicate value in a UNIQUE index or PRIMARY KEY, an of the old row occurs. For example, if column a is declared as UNIQUE and contains the value 1, the following two statements have similar effect: INSERT INTO t1 (a,b,c) VALUES (1,2,3) ON DUPLICATE KEY UPDATE c=c+1; UPDATE t1 SET c=c+1 WHERE a=1; (The effects are not identical for an InnoDB table where a is an auto-increment column. With an auto-increment column, an INSERT statement increases the auto-increment value but UPDATE does not.) If column b is also unique, the is equivalent to this statement instead: UPDATE t1 SET c=c+1 WHERE a=1 OR b=2 LIMIT 1; If a=1 OR b=2 matches several rows, only one row is updated. In general, you should try to avoid using an ON DUPLICATE KEY UPDATE clause on tables with multiple unique indexes. With ON DUPLICATE KEY UPDATE, the affected-rows value per row is 1 if the row is inserted as a new row, 2 if an existing row is updated, and 0 if an existing row is set to its current values. If you specify the CLIENTFOUNDROWS flag to the C API function when connecting to, the affected-rows value is 1 (not 0) if an existing row is set to its current values. If a table contains an AUTOINCREMENT column and inserts or updates a row, the function returns the AUTOINCREMENT value.

The ON DUPLICATE KEY UPDATE clause can contain multiple column assignments, separated by commas. In assignment value expressions in the ON DUPLICATE KEY UPDATE clause, you can use the function to refer to column values from the portion of the statement. In other words, in the ON DUPLICATE KEY UPDATE clause refers to the value of colname that would be inserted, had no duplicate-key conflict occurred. This function is especially useful in multiple-row inserts.

Hello, I'm looking for a solution to write a sql query that inserts a set of data if the data id is not present and otherwise update the set. I have a table with id (char(8)) and value (int(8)). Learn how to INSERT an If Row Does Not Exist (UPSERT) in MySQL. Values is to use the INSERT. ON DUPLICATE KEY UPDATE statement. INSERT statement and add. What I'm trying to do is INSERT subscribers in my database, but IF EXISTS it should UPDATE the row, ELSE INSERT INTO a new row. Ofcourse I connect to the database first and GET the $name, $email a.

The function is meaningful only in the ON DUPLICATE KEY UPDATE clause or statements and returns NULL otherwise. Example: INSERT INTO t1 (a,b,c) VALUES (1,2,3),(4,5,6) ON DUPLICATE KEY UPDATE c=VALUES(a)+VALUES(b); That statement is identical to the following two statements: INSERT INTO t1 (a,b,c) VALUES (1,2,3) ON DUPLICATE KEY UPDATE c=3; INSERT INTO t1 (a,b,c) VALUES (4,5,6) ON DUPLICATE KEY UPDATE c=9; For statements, these rules apply regarding acceptable forms of SELECT query expressions that you can refer to in an ON DUPLICATE KEY UPDATE clause. References to columns from queries on a single table, which may be a derived table. References to columns from queries on a join over multiple tables.

References to columns from DISTINCT queries. References to columns in other tables, as long as the does not use GROUP BY.

One side effect is that you must qualify references to nonunique column names. References to columns from a do not work reliably. To work around this restriction, rewrite the as a derived table so that its rows can be treated as a single-table result set. For example, this statement can produce incorrect results: INSERT INTO t1 (a, b) SELECT c, d FROM t2 UNION SELECT e, f FROM t3 ON DUPLICATE KEY UPDATE b = b + c; Instead, use an equivalent statement that rewrites the as a derived table: INSERT INTO t1 (a, b) SELECT. FROM (SELECT c, d FROM t2 UNION SELECT e, f FROM t3) AS dt ON DUPLICATE KEY UPDATE b = b + c; The technique of rewriting a query as a derived table also enables references to columns from GROUP BY queries. Because the results of statements depend on the ordering of rows from the and this order cannot always be guaranteed, it is possible when logging statements for the master and the slave to diverge. Thus, statements are flagged as unsafe for statement-based replication. Easyfly 4 gratis download.

Such statements produce a warning in the error log when using statement-based mode and are written to the binary log using the row-based format when using MIXED mode. An statement against a table having more than one unique or primary key is also marked as unsafe. (Bug #11765650, Bug #58637) See also. ON DUPLICATE KEY UPDATE on a partitioned table using a storage engine such as that employs table-level locks locks any partitions of the table in which a partitioning key column is updated.

(This does not occur with tables using storage engines such as that employ row-level locking.) For more information, see. Regarding the trick for making LASTINSERTID well defined for updates: INSERT INTO table (a,b,c) VALUES (1,2,3) ON DUPLICATE KEY UPDATE id=LASTINSERTID(id), c=3; This does not work if nothing changes, presumably because MySQL doesn't run the dummy update at all then. If there is an existing record with 3 in column c then LASTINSERTID still won't return the AUTOINCREMENT id afterwards. I'm not sure whether this should be regarded as a bug or not, but it does make the construct less useful. Example:Update-Select-GroupBy I have a table of totals 'v8totals' with PrimaryKey=(tid,tyy,tmm) and a table of records 'bbprepay'. Here's how i keep my totals uptodate when the prepays change. INSERT INTO v8totals (tid,tyy,tmm,finances) SELECT '3218',YEAR(ppdate),MONTH(ppdate),SUM(ppamount) FROM bbprepay WHERE fkuserid='3218' GROUP BY YEAR(ppdate),MONTH(ppdate) ON DUPLICATE KEY UPDATE finances=(SELECT SUM(ppamount) FROM bbprepay WHERE fkuserid='3218' AND tyy=YEAR(ppdate) AND tmm=MONTH(ppdate) GROUP BY YEAR(ppdate),MONTH(ppdate)) It might not be the best way to do an 'Insert otherwise Update' but its working for me.

Hope it helps.:). If you need to update/insert a field and atomically get the previous value, here's a way to do the trick: SET @previousnote:= NULL; INSERT INTO rencontrenotemoilastvotes (id, note) VALUES (1, 2) ON DUPLICATE KEY UPDATE note = IF((@previousnote:= note) NULL IS NULL, VALUES(note), NULL); SELECT @previousnote; Two tricks are actually used here: (anything) NULL is always NULL even if (anything) is NULL. So (anything) NULL IS NULL is always TRUE. @previousnote is set according to the value of a field, and that value is obviously the previous value, not the one being currently computed. That way, a new 'note' is inserted of the 'note' is changed, and the previous value is returned. Best regards, -Frank. Another useful hint at INSERT with UPDATE: create table b (a1 integer,a2 integer, primary key (a1)); insert into b values (1,2),(2,2); select.

from b; +-+-+ a1 a2 +-+-+ 1 2 2 2 +-+-+ insert into b (a1, a2) values(1,2) on duplicate key update b.a2 = IF(VALUES(a2) select. from b; +-+-+ a1 a2 +-+-+ 1 2 2 2 +-+-+ insert into b (a1, a2) values(1,3) on duplicate key update b.a2 = IF(VALUES(a2). The 'work around' suggested in the documentation to obtain the ID of a row updated using the DUPLICATE KEY UPDATE clause of an INSERT statement has a problem in addition to those mentioned by earlier posts. Namely, if you are using INNODB storage engine and have a FOREIGN KEY referencing the primary key of the table being updated, this strategy may fail with: ERROR 1451 (23000): Cannot delete or update a parent row: a foreign key constraint fails. My ultimate approach is to not use the DUPLICATE KEY UPDATE for this purpose.

Rather, I explicitly test for existence using a SELECT, and only perform the INSERT if the SELECT fails. Here is a nice tip for INSERT INTO SELECT ON DUPLICATE KEY UPDATE. Better than Jon Webb's example mentioned above.

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The trick is to use user-defined variable to store computed data, so that it is not need to be computed again. This will also solve Nikolay Pelov's problem in the previous post. Insert into RankAuthor(idAuthor, publicationCount, citationCount, coAuthorCount) select ap.idAuthor, @publicationCount:= count(distinct ap.idPaper), 0, 0 from authorpaper ap group by ap.idAuthor on duplicate key update publicationCount = @publicationCount.