Mysql Round Date To Half Hour
UPDATE:Since you aren't concerned with any 'missing' rows, I'm also going to assume (probably wrongly) that you aren't concerned that the query might possibly return rows for periods that are not from 7AM to 12AM. This query will return your specified result set: SELECT (HOUR(r.time)-7).2+(MINUTE(r.time) DIV 30) AS i, SUM(r.subtotal) AS sumsubtotalFROM Receipts rGROUP BY iORDER BY iThis returns the period index (i) derived from an expression referencing the time column.
For reporting purposes I need a Time table that acts as a lookup table that lists every half hour in a day. It will function the same way as a date table except it's time. I found a great example of a 24 hour table.
For best performance of this query, you probably want to have a 'covering' index available, for example: ON Receipts(`time`,`subtotal`)If you are going to include an equality predicate on the date column (which does not appear in your solution, but which does appear in the solution of the 'selected' answer, then it would be good to have that column as a leading index in the 'covering' index. ON Receipts(`date`,`time`,`subtotal`)If you want to ensure that you are not returning any rows for periods before 7AM, then you could simply add a HAVING i = 0 clause to the query. (Rows for periods before 7AM would generate a negative number for i.) SELECT (HOUR(r.time)-7).2+(MINUTE(r.time) DIV 30) AS i, SUM(r.subtotal) AS sumsubtotalFROM Receipts rGROUP BY iHAVING i = 0ORDER BY iPREVIOUSLY:I've assumed that you want a result set similar to the one you are currently returning, but in one fell swoop. This query will return the same 33 rows you are currently retrieving, but with an extra column identifying the period (0 - 33). Your solution returns the exact results I need and the same way my current loop does.
My only concern is that it still took 9 seconds to run the entire script, while the solution offered by drew at took half a second. Maybe I'm missing something as to why it's taking this long? Also good point about missing rows when no time exists. There is enough data so that it won't be a problem however. I want to reward both answers as correct since they both are, just in different ways.–Aug 1 '12 at 23:50.
Mysql Round Date To Half Hour Lyrics
9 seconds of elapsed time is a lot longer than I would have expected. Drew's solution involves a DATE, but the solution I have doesn't.
Mysql Hours Between Two Dates
Performance should definitely be faster, but I'd really need to review the EXPLAIN and the table definitions, including indexes. The query I provided is going to process every single one of those 150,000 rows, and assign them all into 33 'buckets'. Because of the JOIN operation in this query, it's going to benefit from proper indexes.–Aug 2 '12 at 3:25. One way to make it pure SQL is to use a lookup table. I don't know MySql that well so there maybe alot of improvement to the code. Always use the proper datatypes for your data.
In the case of your date/time columns, it's best to store them as (preferrably UTC zoned) timestamps. This is especially true in that some times don't exist for some dates (for some timzones, hence UTC). You will want an index on this column.Also, your date/time range isn't going to give you what you want - namely, you're missing anything exactly on the hour (because you use a strict greater-than comparison). Always define ranges as 'lower-bound inclusive, upper-bound exclusive' (so, time = '07:00:00' AND time = DATE('2011-09-10')AND calendardate = divisionAND occurredAt.
If a channel is included in your Spectrum TV subscription, you can use your Spectrum username and password to sign in to the TV channel app. Note: After creating a new Spectrum.net username, you'll need to wait 24-72 hours before you can use it to sign in to any TV channel apps. Once you have signed in to the Spectrum TV App, you can stream live TV, watch On Demand content, view and filter the guide and much more. Note: If you are inside home and connected to a Spectrum authorized modem, the application should automatically authorize your username and password. Aug 25, 2017 To watch TV on your computer, open a web browser and search for local stations and major networks. Then, go to the websites, where you can stream the latest episodes of their popular TV shows for free. Watch live and On Demand shows, and manage your DVR, whether you're home or on the go. How to watch spectrum channels from computer. Dec 18, 2017 How to install Spectrum TV for PC using APK. Download and save Spectrum TV APK on your PC. If you are using Windows, download and install BlueStacks 3. If you are using Mac, download and install BlueStacks. Setup your installed emulator according to the instructions explained in the guides. Now open BlueStacks or BlueStacks 3. On Windows, double-click on downloaded Spectrum TV.