I have this table:
I need to query the table and ask the following questions:
How many rows matching uri 'x' exist with unique IP addresses between 'y' and 'z' dates.
I was experimenting with COUNTs but I couldn't seem to get the result I needed...
Try using COUNT(DISTINCT())
Returns a count of the number of rows with different non-NULL expr values.
So your query would be something like
SELECT COUNT( DISTINCT( user_ip ) )
FROM table
WHERE timestamp BETWEEN Y and Z
The DISTINCT keyword enforces that only unique entries are returned in the query. As the above answer by ConroyP mentions you can nest DISTINCT within other functions in SQL. Note that this is has a different function from 'UNIQUE' which enforces uniqueness constraints in the Data Definition Language part of SQL. Some databases also allow you to substitute the keyword UNIQUE for DISTINCT in the query - but this doesn't seem to work everywhere.
Related
The two tables are basically identical with a user id, date and count.
I need to get results for both tables via user id, but match the dates. If a date is missing from either table (ie it is in one table but not the other) I need to assign a 0 for "count" for that returned result. Can this be done in the query or do I need to do this in PHP as well?
Thanks for any suggestions!
I ended up building an array for both table results, then picking the bigger array via count and running a loop through it comparing keys to the smaller array. Thanks everyone for their insight!
You can select from both tables with inner join, and after that you can add condition with WHERE statement, like WHERE date != null, or date != ''.
If you'd like to read more about inner join, this is your site below:
https://www.w3schools.com/sql/sql_join_inner.asp
I am using group by for like statement as i have database structure like this.
I want to get the count of workingzone groupby.but if i try to group by, then wrong output will appear as output will group by 99 and 99, as in figure.
My sql code is:
select count(organization),working_zone from `projects` where `district` = 12 and (`working_zone` = 99 or `working_zone` LIKE "99," or `working_zone` LIKE ",99") group by `organization`;
my desired result is:
count |working_zone
____6| 99
____3| 100
(99),(,99),(99,) should be grouped by doing sum and result should be 6.
You have an awful data structure -- although I wouldn't be surprised if the data is okay and you are really working off the result of a (reasonable) query. You should not be storing raw data in comma-delimited lists. Instead, use junction tables.
Why is having a separate row for each pair the SQLish way of storing data? Consider these reasons:
SQL has pretty based string functions (compared to other programming environments).
Data should be stored in its native type; don't store numbers as strings.
Foreign key relationships should be explicitly declared, and you can't declare a foreign key relationship using comma-delimited strings.
The primary SQL mechanism for optimizing queries are indexes, and comma-delimited lists preclude the use of indexes.
Sometimes, though, you are stuck with someone else's bad design decisions. If so, one solution uses a table of working zones:
select count(*), wz.working_zone
from projects p join
working_zones wz
on find_in_set(wz.working_zone, p.working_zone) > 0
where p.district; = 12 and
find_in_set(99, p.working_zone) > 0
group by wz.working_zone;
SELECT COUNT(organization),working_zone FROM table WHERE working_zone HAVING '99'
UNION ALL
SELECT COUNT(organization),SUBSTRING(working_zone,4) FROM table WHERE working_zone = '99,100'
I am writing a complex MySQL query. My actual query is more complex than I mentioned below.
I have a table named example and columns are id, name, option_1, option_2 . Of course id column is PK . I want to retrieve like this:
SELECT `id`,`name`,count(`option_1`),count(`option_2`)
My problem is I want to use "GROUP BY `id`" for count(`option_1`) and "GROUP BY `name`" for count(`option_2`) respectively. Now I have to break down it into multiple code in my php code.
How can I achieve what I want in a single query?
What you're asking for doesn't make a ton of sense. You want option 1 grouped by id and option 2 grouped by name, and you want to show all four columns in one result set.
First of all, if id is a primary key, then the count will just be the number of rows in the table since there will be no duplicate ids.
Second, even if id wasn't a primary key, and there were duplicate values, the grouping is different, so the counts represented in your result set would be grouped incorrectly.
Given that id is a primary key, perhaps your intention is actually to get a total count of the rows in the table. Perhaps this query would suit your needs?
SELECT
name,
COUNT(option_2) AS options
FROM
example
GROUP BY
name
UNION ALL
SELECT
'Total' AS name,
COUNT(*) AS options
FROM
example
This should get you a count of all the option_2 values, grouped by name, with the final row having a name of 'Total' and the count being the total number of rows in the table.
Aside from that, I'm not sure you're going to find the answer you're looking for due to the problems you would encounter matching up groupings.
I have the following tables:
TableFinal
column id, with first row having value 1
column numbers, with first row having value `1,5,6,33,2,12,3,4,9,13,26,41,59,61,10,7,28`
And
TablePick
column id, with first row having value 1
column numbers, with first row having value 2,12,26,33
I want to check if the numbers from TablePick, column "selected" are contained in the column "numbers" of TableFinal.
I have to mention that in TablePick, the numbers in column "selected" are ordered ASC, while in TableFinal, the numbers in column "numbers" are shuffled.
Usually I would put each of these in an array using PHP and then intersect the 2 arrays and count the resulted array. But in MYSQL, it is not that simple, so practically I have no idea where to start.
Maybe I should create an ARRAY_INTERSECT function? Or do we have a simpler solution?
SELECT * FROM TablePick p RIGHT JOIN TableFinal f ON f.id=p.id WHERE ARRAY_INTERSECT(p.selected,f.numbers)
Sorry to say so, but your schema needs some serious maintenance: NEVER EVER store more than one information in one field, if you need to access them separately.
You need a pair of join tables, where instead of the first row (1, "1,5,6,33,2,12,3,4,9,13,26,41,59,61,10,7,28") you have the rows
(1,1)
(1,5)
(1,6)
(1,33)
...
and instead of the row (1, "2,12,26,33") you have the rows
(1,2)
(1,12)
(1,26)
(1,33)
Now you query is simply:
SELECT ... FROM TableFinal
INNER JOIN TABLE TablePick ON TableFinal.number=TablePick.number
WHERE TableFinal.id=1
AND TablePick.id=1
EDIT
Please understand, that even if this were possible without MySQL abuse, it would be a performance killer, once the number of rows start to rise: We are talking of n*m array intersects, if the tables have n and m rows respectivly.
I have a table (client) with 20+ columns that is mostly historical data.
Something like:
id|clientID|field1|field2|etc...|updateDate
If my data looks like this:
10|12|A|A|...|2009-03-01
11|12|A|B|...|2009-04-01
19|12|C|B|...|2009-05-01
21|14|X|Y|...|2009-06-11
27|14|X|Z|...|2009-07-01
Is there an easy way to compare each row and highlight the differences in the fields?
I need to be able to simply highlight the fields that changed between revisions (except for the key and the date of course)
There may be multiple fields updated in each new row (or just one).
This would be on a client by client basis so I could select on the clientID to filter.
It could be on the server or client side, which ever is easiest.
More details
I should expand my description a little:
I'm looking to just see if there was a difference between the fields (one is different in any way). Some of the data is numeric, some is text others are dates. A more complete example might be:
10|12|A|A|F|G|H|I|J|...|2009-03-01
11|12|A|B|F|G|H|I|J|...|2009-04-01
19|12|C|B|F|G|Z|I|J|...|2009-05-01 ***
21|14|X|Y|L|M|N|O|P|...|2009-06-11
27|14|X|Z|L|M|N|O|P|...|2009-07-01
I'd want to be able to isplay each row for clientID 12 and highlight B from row 11 and C & Z from row 19.
Any expression in SQL must reference columns only in one row (barring subqueries).
A JOIN can be used to make two different rows into one row of the result set.
So you can compare values on different rows by doing a self-join. Here's an example that shows joining each row to every other row associated with the same client (excluding a join of a row to itself):
SELECT c1.*, c2.*
FROM client c1
JOIN client c2 ON (c1.clientID = c2.clientID AND c1.id <> c2.id)
Now you can write expressions that compare columns. For example, to restrict the above query to those where field1 differs:
SELECT c1.*, c2.*
FROM client c1
JOIN client c2 ON (c1.clientID = c2.clientID AND c1.id <> c2.id)
WHERE c1.field1 <> c2.field1;
You don't specify what kinds of comparisons you need to make, so I'll leave that to you. The key point is that in general, you can use a self-join to compare rows in a given table.
Re your comments and clarification: Okay, so your "difference" is not simply by value but by ordinal position of the row. Remember that relational databases don't have a concept of row number, they only have order of rows with respect to some order you must specify in an ORDER BY clause. Don't confuse the "id" pseudokey with row number, the numbers are assigned as monotonically increasing only by coincidence of their implementation.
In MySQL, you could take advantage of user-defined variables to achieve the effect you're looking for. Order the query by clientId and then by id, and track values per column in MySQL user variables. When the value in a current row differs from the value in the variable, do whatever highlighting you were going to do. I'll show an example for one field:
SET #clientid = -1, #field1 = '';
SELECT id, clientId, field1, #clientid, #field1,
IF(#clientid <> clientid,
((#clientid := clientid) AND (#field1 := field1)) = NULL,
IF (#field1 <> field1,
(#field1 := field1),
NULL
)
) AS field1_changed
FROM client c
ORDER BY clientId, id;
Note this solution is not really different from just selecting all rows with plain SQL, and tracking the values with application variables as you fetch rows.