I loaded the result set with top 10 rows as follows.
SELECT * FROM Persons LIMIT 10;
Now how to select next 10 rows.? Like what in google search results can be toggled between search results.
Pardon if question sounds silly because i didn't found any relevant answer on google.
You can give the LIMIT clause a starting point, like this:
SELECT * FROM Persons LIMIT 50, 10;
This would mean the offset is 50 (it skips the first 50 rows), and the next 10 rows are selected. See also in the manual: MySQL SELECT Syntax.
Use OFFSET + LIMIT to do this
SELECT * FROM Persons
ORDER BY somecol
OFFSET 10 LIMIT 10 -- LIMIT 10 OFFSET 10
For Mysql
SELECT * FROM Persons
ORDER BY somecol
LIMIT 10 OFFSET 10 --LIMIT 10,10
Note: Make sure you add Order by to get meaningful results
Related
I have database with about 500K row in it. I want get random row from row like 1 to 5000 and its limit result limit need like 100.
My current query is like below
'SELECT * FROM user where status='0' LIMIT 10,100'
what should I change or use for get limited random row, so I can get fast result without memory consume ?
Thanks
A database table is an unordered set, so you'll have to provide some order to get 1 to 5000 rows (otherwise those will be any 1 to 5000 rows), may be based on userid.
Once you have that, you can limit the rows in subquery and sort by rand() and get first 100 like this:
select *
from (select
*
from user
where status = 0
order by /* set of columns, may be user_id*/
limit 1, 5000
) t order by rand() limit 100;
This query gives you any 100 random rows from your 5000k rows
select * from user where status='0' order by rand() limit 100
Here is my query, which i am using for pagination
SELECT DISTINCT email_list.*, email_counter.phone as e_phone,email_counter.email as e_email,email_counter.marketing as e_marketing
FROM Data_TLS_builders as email_list
LEFT JOIN wp_pato_email_list_counters as email_counter on email_counter.email_id = email_list.URN
LIMIT 120 OFFSET 150
Rather than starting at 120 and finishing at 150, which should display 30 results, mysql is returning 120 results and ignoring the OFFSET. I have tried LIMIT 120,150 and still the same?
Any idea how to solve?
SELECT DISTINCT email_list.*, email_counter.phone as e_phone,email_counter.email as e_email,email_counter.marketing as e_marketing FROM Data_TLS_builders as email_list LEFT JOIN wp_pato_email_list_counters as email_counter on email_counter.email_id = email_list.URN LIMIT 30 OFFSET 120
Limit specifies number of records.
OFFSET specifies upto how many records it should skip.
The above query returns 30 records from 121.
You have to switch the limit parameters.
Solution 1:
SELECT DISTINCT email_list.*, email_counter.phone as e_phone,email_counter.email as e_email,email_counter.marketing as e_marketing FROM Data_TLS_builders as email_list LEFT JOIN wp_pato_email_list_counters as email_counter on email_counter.email_id = email_list.URN LIMIT 30 OFFSET 120
Solution 2:
SELECT DISTINCT email_list.*, email_counter.phone as e_phone,email_counter.email as e_email,email_counter.marketing as e_marketing FROM Data_TLS_builders as email_list LEFT JOIN wp_pato_email_list_counters as email_counter on email_counter.email_id = email_list.URN LIMIT 120, 30
You can also have a look into the documentation: http://www.w3schools.com/php/php_mysql_select_limit.asp.
LIMIT will tell mysql HOW MANY results you want to show.
OFFSET will tell mysql where to START.
if you want to display 30 results starting at 120, it should be:
LIMIT 30 OFFSET 120
or
LIMIT 120, 30
I just want to know how to call after 10 rows in flash column.
I want to call all category = today. Is it possible?
For Example
SELECT * FROM news WHERE category='today' AND flash='true' limit 60
Is this what you're looking for (it's an official solution shown in the MySQL SELECT Syntax)?
SELECT * FROM news
WHERE flash='true'
LIMIT 10, 18446744073709551615;
Update:
After reading your comments, maybe this is what you're looking for:
SELECT *
FROM (SELECT *
FROM `news`
WHERE (`flash` = 'true')
LIMIT 10, 18446744073709551615) `after_flash`
WHERE `after_flash`.`category` = 'today';
Do you mean fetch 60 records from positions 11-70?
SELECT * FROM news WHERE category='today' AND flash='true' limit 10,60
You may need to do an ORDER BY clause as well to sort the data.
Im trying to get a result set that contains the 10 values that are closest to, in this case, the number 3.
I have a database that has values in a column named rated which can be 1,2,3,4 or 5. What im trying to do is query the database and return the first 10 rows that have the values closest to 3. The values can be above 3 or below 3. I should note that these values in the rated column are floats.
I then need to sort these rows in order so that rows with value of 3 are first and then the row with lowest offset (+/-) from 3.
Is there any SQL query that can return atleast the result set of values closest to 3 ? or am i going to have to return the whole db and sort it myself?
To get the first 10 rows with highest value down i used the statement
SELECT * FROM tabs ORDER BY 5 DESC LIMIT 10";
5 refers to the column rated
Is there some way to modify this to do what i want ?
Thanks
If I understand your problem correctly, this should do the trick:
select *
from tabs
order by abs(`rated` - 3) asc
limit 10
Note that it sorts by the difference in ascending order, so those with a difference of 0 will come first.
SELECT * FROM tabs ORDER BY ABS(3 - Rate) ASC LIMIT 10
If I got right what you need try:
select *
from (
select
case when -(3-rated) > 0 then -(3-rated) else (3-rated) end as distance,
tabs.*
from tabs
) subsel
order by distance
limit 10
Let's say I have a list of values, like this:
id value
----------
A 53
B 23
C 12
D 72
E 21
F 16
..
I need the top 10 percent of this list - I tried:
SELECT id, value
FROM list
ORDER BY value DESC
LIMIT COUNT(*) / 10
But this doesn't work. The problem is that I don't know the amount of records before I do the query. Any idea's?
Best answer I found:
SELECT*
FROM (
SELECT list.*, #counter := #counter +1 AS counter
FROM (select #counter:=0) AS initvar, list
ORDER BY value DESC
) AS X
where counter <= (10/100 * #counter);
ORDER BY value DESC
Change the 10 to get a different percentage.
In case you are doing this for an out of order, or random situation - I've started using the following style:
SELECT id, value FROM list HAVING RAND() > 0.9
If you need it to be random but controllable you can use a seed (example with PHP):
SELECT id, value FROM list HAVING RAND($seed) > 0.9
Lastly - if this is a sort of thing that you need full control over you can actually add a column that holds a random value whenever a row is inserted, and then query using that
SELECT id, value FROM list HAVING `rand_column` BETWEEN 0.8 AND 0.9
Since this does not require sorting, or ORDER BY - it is O(n) rather than O(n lg n)
You can also try with that:
SET #amount =(SELECT COUNT(*) FROM page) /10;
PREPARE STMT FROM 'SELECT * FROM page LIMIT ?';
EXECUTE STMT USING #amount;
This is MySQL bug described in here: http://bugs.mysql.com/bug.php?id=19795
Hope it'll help.
I realize this is VERY old, but it still pops up as the top result when you google SQL limit by percent so I'll try to save you some time. This is pretty simple to do these days. The following would give the OP the results they need:
SELECT TOP 10 PERCENT
id,
value
FROM list
ORDER BY value DESC
To get a quick and dirty random 10 percent of your table, the following would suffice:
SELECT TOP 10 PERCENT
id,
value
FROM list
ORDER BY NEWID()
I have an alternative which hasn't been mentionned in the other answers: if you access from any language where you have full access to the MySQL API (i.e. not the MySQL CLI), you can launch the query, ask how many rows there will be and then break the loop if it is time.
E.g. in Python:
...
maxnum = cursor.execute(query)
for num, row in enumerate(query)
if num > .1 * maxnum: # Here I break the loop if I got 10% of the rows.
break
do_stuff...
This works only with mysql_store_result(), not with mysql_use_result(), as the latter requires that you always accept all needed rows.
OTOH, the traffic for my solution might be too high - all rows have to be transferred.