Αποτελέσματα Αναζήτησης
9 Ιουν 2011 · delete from YourTable where YourTable.columnA in (select columnA from YourTable group by column A having count(*) > 1)
4 Απρ 2021 · CREATE TABLE `data` ( `id` int(6) NOT NULL AUTO_INCREMENT, `channel_id` int(11) DEFAULT NULL, `timestamp` bigint(20) NOT NULL, `value` float NOT NULL, PRIMARY KEY (`id`), KEY `IDX_ADF3F36372F5A1AA` (`channel_id`), ) ENGINE=InnoDB AUTO_INCREMENT=2126679551
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.
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)”. Single-Table Syntax. DELETE [LOW_PRIORITY] [QUICK] [IGNORE] FROM tbl_name [[AS] tbl_alias]
In its simplest form, the syntax for the DELETE statement in MySQL is: DELETE FROM table. [WHERE conditions]; However, the full syntax for the DELETE statement in MySQL is: DELETE [ LOW_PRIORITY ] [ QUICK ] [ IGNORE ] FROM table. [WHERE conditions] [ORDER BY expression [ ASC | DESC ]] [LIMIT number_rows]; Parameters or Arguments. LOW_PRIORITY.
14 Ιουν 2024 · The MySQL DELETE statement deletes one or more existing records from a table. It is commonly used with the WHERE or JOIN clause. It is a Data Manipulation Language (DML) statement. Generally, you cannot ROLLBACK (undo) after performing the DELETE statement.
Use the DELETE statement to delete one or more rows from a table. Use the DELETE statement without a WHERE clause to delete all rows from a table. Use the DELETE statement with a LIMIT clause to delete several rows from a table.
