Αποτελέσματα Αναζήτησης
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.
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> DROP TABLE IF EXISTS mytable; mysql> CREATE TABLE mytable ( -> id INT UNSIGNED NOT NULL PRIMARY KEY, -> a VARCHAR(10), -> b VARCHAR(10), -> c INT -> ); mysql> INSERT INTO mytable -> VALUES (1, 'abc', 'qrs', 1000), -> (2, 'abc', 'tuv', 2000), -> (3, 'def', 'qrs', 4000), -> (4, 'def', 'tuv', 8000), -> (5, 'abc', 'qrs', 16000), -> (6, 'def ...
This tutorial shows you how to use the MySQL GROUP BY clause to group rows into subgroups based on columns or values returned from an expression.
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)”.
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.
