I want to display the logs to recent activities page ordered by date. Now I was trying to execute this to my mysql
"SELECT * FROM tracking_log.editlog, tracking_log.deletelog, tracking_log.loginlog, tracking_log.logoutlog ORDER BY time ASC";
but it always says
Column 'time' in order clause is ambiguous
all of the tables have a time column, format by datetime (0000-00-00 00:00:00)
How am I going to fetch them ordered by time?
Thanks in advance!
By which table's time column you want to order?
Assuming you want to order the result set by tracking_log.editlog.time column then the query would look like below:
SELECT
*
FROM tracking_log.editlog, tracking_log.deletelog,
tracking_log.loginlog, tracking_log.logoutlog
ORDER BY tracking_log.editlog.time ASC;
Just in case if all of the time columns in the respective table don't contain NOT NULL values at the same time then you need to use COALESCE I guess.
Query using COALESCE
SELECT
*
FROM tracking_log.editlog, tracking_log.deletelog,
tracking_log.loginlog, tracking_log.logoutlog
ORDER BY
COALESCE(tracking_log.editlog.time , tracking_log.deletelog.time, tracking_log.loginlog.time,tracking_log.logoutlog.time) ASC;
'tracking_log' is your database name, and you're selecting multiple tables from that database, so you need to specify from which table you want to order 'time' by:
select * from tracking_log.editlog, tracking_log.deletelog ORDER BY tracking_log.editlog.time ASC
or whichever table from your database you want to use 'time' from. This will fix the error but won't return any results because you have multiple tables in a SELECT clause without anything relating them together.
You'll need to specify some common columns on which you want to return results rather than getting the wildcard and then UNION the tables to aggregate the results. For example, if you have common columns userID, description and time in all your tables, you could do the following:
(SELECT userID, description, time FROM tracking_log.editlog)
UNION
(SELECT userID, description, time FROM tracking_log.deletelog)
ORDER BY time
Related
I ran into an error I cant seem to come out of.
am not too good with unions
I want to loop through 4 different tables(using union all) and manipulate their values to fit my needs.
I also need to use single 'ORDER by Date DESC' (Date are integer values) for the whole union all, so that I can arrange the output in a pattern,
when I add the 'order by date desc ' to it, code doesn't work . and when I remove it , the values of the second query are attached to the names of the first query, am sooo confused.
I tried "Select * from table_name where..... it idnt work in this case , that's why I had to bring out all table_names I need to the query,
Basically , I want to echo each value from the query uniquely when I need to,
any help is appreciated, thanks
<?php
$q114="(SELECT id AS id1,text_post AS text_post1,likes AS likes1
FROM timeline_posts WHERE email='$owner_email')
UNION ALL (SELECT pic_comment AS pic_comment2, comments AS comments2, date AS date2
FROM pictures WHERE email='$owner_email')
UNION ALL (SELECT image AS image3,likes AS likes3, comments AS comments3
FROM profile_pics WHERE email='$owner_email')
UNION ALL (SELECT likes AS likes4, comments AS comments4, date AS date4
FROM friends_timeline_post WHERE timeline_email='$owner_email')
ORDER BY 'date' DESC";
$pages_query=mysqli_query($connect,$q114);
while($fetch9=mysqli_fetch_assoc($pages_query))
{
print_r($fetch9['likes3'] );
//a lot of work to be done here
}
?>
For "unioning" the results of multiple selects and ordering those results by a column name across all the results of the multiple selects, column names must be the same in all selects.
You could add a column to all selects that would contain your "digit" in order to still be able to distinguish between let say "likes1" and "likes2" even if their column name is "likes" for all the selects that you "unioned".
I want per day sales item count so for that one i already created query but it takes to much around 55.585s and query is
Query :
SELECT
td.db_date,
(
select count(*) from order as order where DATE(order.created_on) = td.db_date
)as day_contribute
FROM time_dimension as td
So can any one please let me know how may i optimized this query and reduce execution time.?
You can modify your query to join like:
SELECT
td.db_date, count(order.id) as day_contribute
FROM time_dimension as td
LEFT JOIN order ON DATE(order.created_on) = td.db_date
GROUP BY td.db_date;
I do not know your primary id key for table order - so used just "order.id". Replace it with your.
Also it is very important - test if you have index on td.db_date field.
And one more important thing - better to avoid using DATE(order.created_on). Because it is mean that DATE() method will be called each time when DB will compare dates. If it is possible - convert order.created_on to same format as td.db_date. Or join by other fields. That will add speed too.
First you should make sure you have index on created_on column in order table.
However if you have many records in time_dimension and many records in order table it might be hard to optimize the query, because for each record from time_dimension you need to search in order table.
You can also change count(*) into count(order_id) (assuming primary key in order table is order_id) or add extra column with date only in order table (created_on_date with date only and index on this column) so your query could look like this:
SELECT
td.db_date,
(
select count(order_id) from order where order.created_on_date = td.db_date
)as day_contribute
FROM time_dimension as td
However it's possible the execution time might be too high if you have many records in both tables, so it might be necessary to create one extra table where you hold number of orders for each day and update it in cron or when adding/updating/deleting records in order table
I currently have a table called cc_site, in this table I store the results of pings from different ip addresses.
The table has four fields:
auto increment ID field
date (which includes time)
IP address
status (used to determine if the ping was successful or not).
I'm trying to create a query which will give me the latest result based off the date field for an individual ip address. The code I'm currently using is below but it doesn't work unless the IP I'm using in the query is the latest entry in the table.
$query = "SELECT *
FROM cc_site
WHERE ip='$host'
AND Date IN (
SELECT max(date)
FROM cc_site
)";
I knew the query is incorrect however I have not been able to find code that would perform the query I need.
Any help would be great.
No need of that sub-query. Use can use ORDER and LIMIT instead -
SELECT * FROM cc_site WHERE ip='$host' ORDER BY `date` DESC LIMIT 1
This will sort the records in descending order according to date and return the record with highest record.
select * from cc_site
where ip='$host' and date in(select max(date) from cc_site where ip='$host');
I think this might give you the answer
Whenever a query like
"select * from table where userid=xx" is done, the mysql fetches these values from
first row to last row of table.
But I want to select from last to first so that recently updated values are displayed first in the results.
I cannot do "select * from table where userid=xx order by time DESC" because there is no time column in table.
I just want recently updated items in the table displayed first.
$result= mysql_query("SELECT
(SELECT column FROM table WHERE [condition] ORDER BY column LIMIT 1) as 'first',
(SELECT column FROM table WHERE [condition] ORDER BY column DESC LIMIT 1) as 'last'");
$row=mysql_fetch_array($result);
echo $row['first'];
echo $row['last'];
If you have any auto-incrementing field you could sort by that desc.
You must provide a column to order by in order to guarantee results. So you will have to either change your table structure or make a decision on what to order by.
A hack would be to pull in the data in the order presented into an array, then start popping off the bottom of that array.
You either have to have a timestamp, or autoincrement id, or some other column that you want to sort by.
Just because you get rows in a certain order from a database when not using an ORDER BY clause, does not mean that they are guaranteed to be returned in that order. It also doesn't imply any order in the result set. You need a definitive field that you can use to ORDER BY, or you cannot do what you are wanting to do.
Some hack you can do for that if you don't have columns you can rely on:
SELECT * FROM (SELECT *,(#x:=#x+1) default_ordering FROM `table_name`, (SELECT #x:=0) t2) any_name ORDER BY default_ordering DESC
Alright, I'm trying to figure out why I can't understand how to do this well...
I have two tables:
invoices:
id
userID
amount
date
payments:
id
userID
amount
date
So, the goal here is to join both tables, where the userID matches whatever I want it to be - and then return everything ordered by date (most recent at the top). However, because there is a date field in each of the tables, I'm not sure how MySQL will handle things... will is sort by both dates automatically? Here's what I was thinking...
"SELECT DISTINCT *
FROM invoices,payments
WHERE {$userID} = invoice.userID
OR {$userID} = payments.userID
ORDER BY date DESC";
But, it's starting to become clear to me that maybe this isn't even the right use of a join command... maybe I need to just get all data on each table alone, then try to sort it somehow with PHP? If that's the better method, what's a good way to do this type of DATE sort while keeping all row data in tact?
I should add, the TIME inside the unix timestamp (that's how "date" is stored) is NOT negligible - it should sort by the date and time.
Thanks all...
If the columns of both tables are the same, you can use a UNION
SELECT X.*
FROM ( SELECT `id`,
`userID`,
'INVOICE' AS PTYPE
`amount`,
`date`
FROM `invoices`
WHERE {$userID} = userID
UNION
SELECT `id`,
`userID`,
'PAYMENT' AS PTYPE
`amount`,
`date`
FROM `payments`
WHERE {$userID} = userID
) X
ORDER BY X.`date`
EDIT
Read the relevant section of the MySQL manual on UNIONS. There are other ways of phrasing this, but this is my preferred style - it should be clear to anybody reading that the ORDER BY clause applies to the result of both sides of the UNION. A carelessly written UNION - even with an ORDER BY - may still leave the final resultset in indeterminate order.
The purpose of the PTYPE is that this query returns an extra column called PTYPE, that indicates whether each individual row is an INVOICE or a PAYMENT... ie. which of the two tables it comes from. It's not mandatory, but can often be useful within a union
Because you have two identical fields named date, MySQL will not know which one you're trying to order by.
"SELECT DISTINCT *
FROM invoices,payments
WHERE {$userID} = invoice.userID
OR {$userID} = payments.userID
ORDER BY invoices.date, payments.date DESC";
This would sort on the invoice date, then the payment date - if that's what you are trying to find out
If your data tipe is Date, Timestamp, or anything related, the SGBD will order it properly. If that was what you've asked.
But if the datatype is String, even when dates is store, it will not sort the way you want.