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Nov 10, 2014 · If I DELETE all rows and then repopulate the table (1million rows), a typical query takes 1s to come back. If instead I TRUNCATE the table, and repopulate it in exactly the same way, a typical query takes 0.05s to come back. YMMV, but for whatever reason for me on MariaDB 10.3.15-MariaDB-log DELETE seems to be ruining my index.
2. TRUNCATE TABLE table_name. Is a DDL (Data Definition Language), you can delete all data and clean identity. If you want to use this, you need DDL privileges in table. DDL statements example: CREATE, ALTER, DROP, TRUNCATE, etc. DELETE FROM table_name / DELETE FROM table_name WHERE 1=1 (is the same) Is a DML (Data Manipulation Language), you ...
Mar 28, 2018 · 2) add a constraint on the duplicated columns AND the new column. alter table mytable add constraint preventdupe unique (mycol1, mycol2, tokeep); 3) set the boolean column to true. This will succeed only on one of the duplicated rows because of the new constraint. update ignore mytable set tokeep = true;
The quick fix is to add SET SQL_SAFE_UPDATES=0; before your query : SET SQL_SAFE_UPDATES=0; Or. close the safe update mode. Edit -> Preferences -> SQL Editor -> SQL Editor remove Forbid UPDATE and DELETE statements without a WHERE clause (safe updates) . BTW you can use TRUNCATE TABLE tablename; to delete all the records .
May 25, 2017 · I had a use case of deleting 1M+ rows in the 25M+ rows Table in the MySQL. Tried different approaches like batch deletes (described above). I've found out that the fastest way (copy of required records to new table): Create Temporary Table that holds just ids. CREATE TABLE id_temp_table ( temp_id int);
Dec 20, 2012 · Here's a working example. Note that the COLUMN keyword is optional, as MySQL will accept just DROP IsDeleted. Also, to drop multiple columns, you have to separate them by commas and include the DROP for each one. ALTER TABLE tbl_Country. DROP COLUMN IsDeleted, DROP COLUMN CountryName; This allows you to DROP, ADD and ALTER multiple columns on ...
Simply drag and drop the table from the Catalog Tree to the Design area. Then you will see the table gets inserted there. From there, right-click on the table and select delete table. Then the table will get deleted from the whole project (assuming correspondent objects which are needed deleting as well).
Mar 17, 2009 · Since you are selecting multiple tables, The table to delete from is no longer unambiguous. You need to select: DELETE posts FROM posts. INNER JOIN projects ON projects.project_id = posts.project_id. WHERE projects.client_id = :client_id. In this case, table_name1 and table_name2 are the same table, so this will work: DELETE projects FROM posts ...
Dec 17, 2010 · FROM (SELECT id. FROM tableE. WHERE arg = 1 AND foo = 'bar') x); will work just fine: Query OK, 1 row affected (3.91 sec) Wrap your subquery up in an additional subquery (here named x) and MySQL will happily do what you ask.
Sep 29, 2012 · An interesting fact. I was sure TRUNCATE will always perform better, but in my case, for a database with approximately 30 tables with foreign keys, populated with only a few rows, it took about 12 seconds to TRUNCATE all tables, as opposed to only a few hundred milliseconds to DELETE the rows.
