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9 Ιουν 2011 · delete from YourTable where YourTable.columnA in (select columnA from YourTable group by column A having count(*) > 1)
The GROUP BY statement groups rows that have the same values into summary rows, like "find the number of customers in each country". The GROUP BY statement is often used with aggregate functions ( COUNT() , MAX() , MIN() , SUM() , AVG() ) to group the result-set by one or more columns.
4 Απρ 2021 · My ultimate goal is to add a unique index which fails due to the duplicates. The duplicates are: select channel_id,timestamp,count(*) cnt. from data. group by channel_id,timestamp having cnt>1.
16 Απρ 2024 · Deleting a MySQL user removes the user's account and the associated grant table privileges. Only admins with global CREATE USER or DELETE privileges can remove another user from MySQL. In this tutorial, learn how to remove one or more MySQL user accounts using the DROP USER statement.
MySQL 9.1 Reference Manual / ... / / / DELETE Statement. 15.2.2 DELETE Statement. DELETE is a DML statement that removes rows from a table. A DELETE statement can start with a WITH clause to define common table expressions accessible within the DELETE. See Section 15.2.20, “WITH (Common Table Expressions)”.
To use DROP USER, you must have the global CREATE USER privilege, or the DELETE privilege for the mysql system schema. When the read_only system variable is enabled, DROP USER additionally requires the CONNECTION_ADMIN privilege (or the deprecated SUPER privilege).
22 Δεκ 2011 · What is the fastest method to convert the following query: SELECT COUNT(*) as c FROM tbl_fields. WHERE fieldnotes IS NULL. GROUP BY fieldno,fieldserial,id,fielddate,fieldsid . HAVING COUNT(*) > 1; ... into one that will delete duplicated records? The table does not have any primary keys and contains several million entries. mysql. duplication.
