Here is an interesting scenario.
Let’s say you are looking at a time, like 9:42 AM and want to know which 15 minute slot it fits into. The answer is 9:30 – 9:45. But how would you get this answer thru Excel formulas?
Excel formula to find slot from time:
Assuming A1 contains the input time, here is one formula that tells you the time slot.
=TEXT(TIME(HOUR(A1),INT(MINUTE(A1)/15)*15,0),”hh:mm”)&” – “&TEXT(TIME(HOUR(A1),(INT(MINUTE(A1)/15)+1)*15,0),”hh:mm”)
Whoa!, that’s long. Let’s examine the inner workings of this beast.
Logic: We need to figure out both lower & upper boundaries of fifteen minute slot for time in A1. The lower boundary is quotient of A1/15 minutes multiplied by 15. For example, 09:42’s lower boundary is 09:30. The upper boundary is lower boundary + 15 minutes.
Implementation:
INT(MINUTE(A1)/15) * 15 portion: this part of the formula tells us the minutes. We extract the minute part of A1 (using MINUTE(A1)) and divide it with 15. We then take only the integer portion of this division and multiply that with 15 again. This gives us the minute portion of lower boundary of our time slot.
TIME(HOUR(A1), INT(..)*15, 0) portion: We then create a time value using the TIME formula by using the same hour as A1, minutes from lower boundary calculation using the INT(…)* 15 and 0 as seconds.
TEXT(TIME(…), “hh:mm”) portion: This will convert the time value to text formatted as hh:mm.
So far we have constructed the lower boundary of time slot. The upper boundary part of the formula is similar with one minor change. Go figure it out.
How to find 1 hour time slot?
Let’s say you want to find the time slot on hourly basis, then what?
Below formula does the job.
=HOUR(A1)&”:00 – ” & (HOUR(A1)+1) & “:00”
What if your time slots are not uniformly spaced?
The above approaches work fine as long as your time slots are uniformly spaced (ie 15 minutes, 1 hour, 4 hours or 8 hour apart). What if you have a unique set up? Something like this:
In that case you can use the range lookup method.
Related: read about pricing tier lookup too.
So there you go. For more information about working with date & time values in Excel, check out below material.
- Convert fractional time to proper time in Excel
- Find last day of any month with this simple trick
- 42 tips for Excel time travelers – Must read!!!
- Check if two dates are in same month
- More formulas & tutorials on Excel date & time
A challenge for you:
How would you write the 15 minute time slot formula? Can you figure out other ways to calculate it? Please share your formulas in the comments section. Your time starts now!
One Response to “SQL vs. Power Query – The Ultimate Comparison”
Enjoyed your SQL / Power Query podcast (A LOT). I've used SQL a little longer than Chandoo. Power Query not so much.
Today I still use SQL & VBA for my "go to" applications. While I don't pull billions of rows, I do pull millions. I agree with Chandoo about Power Query (PQ) lack of performance. I've tried to benchmark PQ to SQL and I find that a well written SQL will work much faster. Like mentioned in the podcast, my similar conclusion is that SQL is doing the filtering on the server while PQ is pulling data into the local computer and then filtering the data. I've heard about PQ query folding but I still prefer SQL.
My typical excel application will use SQL to pull data from an Enterprise DB. I load data into Structured Tables and/or Excel Power Pivot (especially if there's lot of data).
I like to have a Control Worksheet to enter parameters, display error messages and have user buttons to execute VBA. I use VBA to build/edit parameters used in the SQL. Sometimes I use parameter-based SQL. Sometimes I create a custom SQL String in a hidden worksheet that I then pull into VBA code (these may build a string of comma separated values that's used with a SQL include). Another SQL trick I like to do is tag my data with a YY-MM, YY-QTR, or YY-Week field constructed form a Transaction Date.
In an application, I like to create a dashboard(s) that may contain hyperlinks that allow the end-user to drill into data. Sometimes the hyperlink will point to worksheet and sometimes to a supporting workbook. In some cases, I use a double click VBA Macro that will pull additional data and direct the user to a supplemental worksheet or pivot table.
In recent years I like Dynamic Formulas & Lambda Functions. I find this preferable to pivot tales and slicers. I like to use a Lambda in conjunction with a cube formula to pull data from a power pivot data model. I.E. a Lambda using a cube formula to aggregate Accounting Data by a general ledger account and financial period. Rather than present info in a power pivot table, you can use this combination to easily build financial reports in a format that's familiar to Accounting Professionals.
One thing that PQ does very well is consolidating data from separate files. In the old days this was always a pain.
I've found that using SQL can be very trying (even for someone with experience). It's largely an iterative process. Start simple then use Xlookup (old days Match/Index). Once you get the relationships correct you can then use SQL joins to construct a well behaved SQL statement.
Most professional enterprise systems offer a schema that's very valuable for constructing SQL statements. For any given enterprise system there's often a community of users that will share SQL. I.E. MS Great Plains was a great source (but I haven't used them in years).
Hope this long reply has value - keep up the good work.