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28 mar 2018 · Deleting duplicates on MySQL tables is a common issue, that usually comes with specific needs. In case anyone is interested, here (Remove duplicate rows in MySQL) I explain how to use a temporary table to delete MySQL duplicates in a reliable and fast way, also valid to handle big data sources (with examples for different use cases).
17 mar 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 ...
So I know in MySQL it's possible to insert multiple rows in one query like so: INSERT INTO table (col1,col2) VALUES (1,2),(3,4),(5,6) I would like to delete multiple rows in a similar way. I know it's possible to delete multiple rows based on the exact same conditions for each row, i.e. DELETE FROM table WHERE col1='4' and col2='5'.
9 lip 2013 · Your second DELETE query was nearly correct. Just be sure to put the table name (or an alias) between DELETE and FROM to specify which table you are deleting from. This is simpler than using a nested SELECT statement like in the other answers. Corrected Query (option 1: using full table name):
30 gru 2010 · However, you can either SELECT then DELETE in separate queries, or nest another subquery and alias the inner subquery result (looks rather hacky, though): SELECT * FROM (. SELECT id FROM posts GROUP BY id HAVING ( COUNT(id) > 1 ) ) AS p. Or use joins as suggested by Mchl. I had a table with 150 duplicate keys.
FROM T1. INNER JOIN T2 ON T1.key = T2.key. WHERE condition; Notice that you put table names T1 and T2 between the DELETE and FROM keywords. If you omit T1 table, the DELETE statement only deletes rows in T2 table. Similarly, if you omitT2 table, the DELETE statement will delete only rows in T1 table. Hope this help.
17 gru 2010 · DELETE T FROM Target AS T RIGHT JOIN (full subquery already listed for the in() clause in answers above) ` AS TT ON (TT.ID = T.ID) And maybe it is answered in the "MySQL doesn't allow it", however, it is working fine for me PROVIDED I make sure to fully clarify what to delete (DELETE T FROM Target AS T).
25 maj 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);
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 ...
The best way is to use IN statement : DELETE from tablename WHERE id IN (1,2,3,...,254); You can also use BETWEEN if you have consecutive IDs : DELETE from tablename WHERE id BETWEEN 1 AND 254; You can of course limit for some IDs using other WHERE clause : DELETE from tablename WHERE id BETWEEN 1 AND 254 AND id<>10; edited Mar 19, 2013 at 15: ...
