group-by

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Will forcing `group by` to sort DESC speed up code up, or slow it down?

In MySQL group by does an implicit order by ASC. This is great if you wanted to add an ORDER BY ASC because then the results are already ordered.开发者_StackOverflow社区[详细]

2023-04-01 00:44 分类：问答
Oracle SQL code syntax standard, Error "not a single-group group function"

I have a block of Oracle SQL code that does work. I figured out I cannot get the cert column and the max(run_time) at the same time.[详细]

2023-03-31 14:17 分类：问答
php mysql compare checboxes returned values with field values

I have a form which sends selected values from a checkbox list to a php script this way: $selected_languages=$_POST[\"selected_languages\"]; // --> \"en-GB,it,fr\"[详细]

2023-03-31 12:36 分类：问答
How do I get a SUM to calculate properly with a join?

So I\'m trying to count the number of parts, number of tasks, the quantity in each job and the time that it took to manufacture each job but I\'m getting some funky results. If I run this:[详细]

2023-03-31 07:58 分类：问答
MYSQL Count group by rows ignoring effect of JOIN and SUM fields on Joined tables

I have 3 t开发者_如何学JAVAables: Orders - id - customer_id Details - id - order_id - product_id - ordered_qty[详细]

2023-03-31 06:07 分类：问答
How can I do a yearly report grouped by month?

I am using the开发者_JS百科 below query to list the number of transactions by month. Does anyone know how can I list by year too. This means that the query returns all my transactions for the whole ye[详细]

2023-03-31 05:27 分类：问答
SQL Server Performance: GROUP BY int vs GROUP BY VARCHAR

Is there a performance difference when grouping by different data t开发者_开发问答ypes? For instance, if I group by INT, will I get better performance than if I group by varchar?I would say GROUP BY I[详细]

2023-03-31 00:54 分类：问答
Indexing for group by + SUM query on mysql

I have a table with the following schema: CREATE TABLE `wordtrend` ( `oid` bigint(20) NOT NULL AUTO_INCREMENT,[详细]

2023-03-30 19:58 分类：问答
Group by day even if data is missing

I want to group results by day: max value for each of the the last 30 days. I came up with : select max(value), DATE(time) from table where time>DATE(\'now\', \'-30 days\') group by DATE(time);[详细]

2023-03-30 19:50 分类：问答
GROUP BY does not remove duplicates

I have a watchlist system that I\'ve coded, in the overview of the users\' watchlist, they would see a list of records, however the list shows duplicates when in the database it only shows the exact,[详细]

2023-03-30 12:02 分类：问答