Αποτελέσματα Αναζήτησης
9 Ιουν 2011 · delete from table where columnA in ( select columnA from ( select columnA from YourTable group by columnA having count(*) > 1 ) t )
2 Μαρ 2018 · MySQL Delete with Group By and Having clauses. To achieve this exploit with a single simple MySQL command, we are using two useful functions: 1. GROUP_CONCAT () This function returns a string result with the concatenated non-NULL values from a group. It returns NULL if there are no non-NULL values. 2.
The DELETE statement deletes rows from tbl_name and returns the number of deleted rows. To check the number of deleted rows, call the ROW_COUNT() function described in Section 14.15, “Information Functions”. Main Clauses. The conditions in the optional WHERE clause identify which rows to delete.
4 Απρ 2021 · DELETE t1 FROM data t1 JOIN data t2 USING (channel_id,timestamp) WHERE t1.id > t2.id
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.
If the query does not use GROUP BY (which usually imposes its own ordering regardless) and you prefer a particular key ordering, you can invoke JSON_OBJECTAGG() as a window function by including an OVER clause with an ORDER BY specification to impose a particular order on frame rows.
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.
