im making a url shortener and im using the id for my hash
but theres a problem with auto incre mysql
URL tabel
id short_hashbase62
1 1
2 2
3 3
4 4
6 6
7 7
8 8
12 c
the missing values are 5 and 9 10 11
question: how could i select the 5 with mysql? then the second select should be 9, and forth on.
there are some similar question but its to complex to understand;
Detect missing values in a (auto-incremented) sequence
Aligning sequences with missing values
Related
In my mysql database
I have to write stored procedure.
I have table DATE which has 4 Columns
Table: DATE
Sq number(auto generated) From_Date To_date value
2 20170112 20170115 3
3 20170116 20170220 5
4 20170221 20170301 7
and so on
so if I get data which has to be added to table
from and to as 20170119 and 20170201 and value 6
then my table should look like
Table:DATE
Sq number(auto generated) From_Date To_date value
2 20170112 20170115 3
3 20170116 20170118 5
4 20170221 20170301 7
5 20170119 20170201 6
6 20170202 20170220 5
is there any algorithm or any logic to implement this kind of situation and handle all other possibilities
Not an answer, but too long for a comment...
If it was me, I'd revise the question, e.g.
start_val end_val
3 5
6 11
What would be the effect of bringing the values 4 and 8 into this table?
I am trying to stop duplicate entry's into my database (below). eg it will come up with an error message if the vechID, Collection date, and return date is the same. I am opening my table in design view and clicking indexes and then indexing the relevant fields. but it wont work let me and keeps saying no due to duplicate values. is this the correct method
Booking ID VechID CuID Collection date Return date
1 3 7 01/07/2017 10/07/2018
2 1 7 23/04/2017 16/05/2018
3 2 1 17/05/2017 28/05/2018
4 4 2 15/05/2017 20/05/2018
5 5 2 01/06/2017 24/06/2018
6 6 2 22/07/2017 29/08/2018
7 4 8 01/07/2017 15/07/2018
8 8 8 01/08/2017 20/08/2018
9 8 2 21/01/2017 20/01/2018
10 4 8 25/09/2017 02/10/2018
13 8 8 25/09/2017 02/10/2018
Yes, you need to create a unique index on the fields (vechID, Collection date, return date).
Of course you can't do that if you already have data in your table that violates this unique index.
Use the query wizard for Duplicate Search to find and delete them.
So I have a table on a sub report that on the first page has 3 rows of data like this.
(I would post pictures but it wont let me)
Column Column 2 Column 3
1 4 7
2 5 8
3 6 9
Then on the next page the table looks like this.
Column Column 2 Column 3
1 4 7
2 5 8
3 6 9
1 4 7
2 5 8
3 6 9
And so on. Each page has the 3 rows repeated an extra time. The data is all correct at least. Anyone know what could be causing this to happen?
*edited the data to be a little easier to understand
I am working on NGSim Traffic data, having 18 columns and 1180598 rows in a text file. I want to smooth the position data, in the column 'Local Y'. I know there are built-in functions for data smoothing in R but none of them seem to match with the formula I am required to apply. The data in text file looks something like this:
Index VehicleID Total_Frames Local Y
1 2 5 35.381
2 2 5 39.381
3 2 5 43.381
4 2 5 47.38
5 2 5 51.381
6 4 8 504.828
7 4 8 508.325
8 4 8 512.841
9 4 8 516.338
10 4 8 520.854
11 4 8 524.592
12 4 8 528.682
13 4 8 532.901
14 5 7 39.154
15 5 7 43.153
16 5 7 47.154
17 5 7 51.154
18 5 7 55.153
19 5 7 59.154
20 5 7 63.154
The above data columns are just example taken out of original file. Here you can see 3 vehicles, with vehicle IDs = 2, 4 and 5 but in fact there are 2169 vehicles with different IDS. The column Total_Frames tell us how many times vehicle Id of each vehicle is repeated in the first column, for example in the table above, vehicle ID 2 is repeated 5 times, hence '5' in Total_Frames column. Following is the formula I am required to apply to remove data noise (smoothing) from column 'Local Y':
Smoothed Position Value = (1/(Summation of [EXP^-abs(i-k)/delta] from k=i-D to i+D)) * ( (Summation of (Local Y) *[EXP^-abs(i-k)/delta] from k=i-D to i+D))
where,
i = index #
delta = 5
D = 15
I have tried using the built-in functions, which I know of, but they don't smooth the data as required. My question is: Is there any built-in function in R which can do the data smoothing in the way of given formula or which could take this formula as an argument? I need to apply the formula to every value in Local Y which has 15 values before and 15 values after them (i-D and i+D) for same vehicle Id. Can anyone give me any idea how to approach the problem? Thanks in advance.
You can place your formula in a function and then use the apply function of R to apply it to the elements in your "Local Y" column of the dataframe
This question already has an answer here:
Mysql query to select a distinct column and the count of a value in another column where column like distinct coumn?
(1 answer)
Closed 9 years ago.
My data table is as below:
ID WEEK RESULT
1 13 GOOD
2 13 BAD
3 13 GOOD
4 13 WORST
5 14 GOOD
6 14 BAD
7 14 WORST
8 15 BAD
9 15 WORST
I need a sql query to create an array as below:
WWEK GOOD_RESULT BAD_RESULT WORST_RESULT TOTAL
13 2 1 1 4
14 1 1 1 3
15 0 1 1 2
Can anyone please help me to find an appropriate mysql query?
SELECT
WEEK,
SUM(RESULT='GOOD') As GOOD_RESULT,
SUM(RESULT='BAD') As BAD_RESULT,
SUM(RESULT='WORST') AS WORST_RESULT,
COUNT(*) As TOTAL
FROM YourTable
GROUP BY
WEEK
Please see fiddle here.