The following database generated by (select * from users).How can i display the recent rows according to time(i.e for time i had used date +%s).But here it displays all timing .I nee dthe rows with the recent update time.
| time | userid | groupid |
+------------+----------+-----------+
| 1477044791 | spolishe | MEMS |
| 1477044791 | ssarkar | HCG |
| 1477044791 | svaranas | PDSP_DES |
| 1476868065 | dnehra | HCG |
| 1476868065 | dprabhu | PDSP_DES |
My expected Output:(but it sould be generated by using some linux commands like date +%s).Is there any linux commands which fetches the only the last recent time rows (or) Is it possible to use inside insert mysql query by storing in some variable name.
| time | userid | groupid |
| 1477044791 | spolishe | MEMS |
| 1477044791 | ssarkar | HCG |
| 1477044791 | svaranas | PDSP_DES |
Do you want to represent the time in proper date formant? if so;
select from_unixtime(time), * from user order by time desc
You could specify that you only want items where the time is equal to that of the largest value that column holds in the table.
SELECT * FROM users where time = (Select max(time) from users);
Related
I have already created table I want to add extra row when adding extra row the created extra row goes up. I want that row at the bottom.
MariaDB [armydetails]> insert into armydetails values('r05','Shishir','Bhujel','Jhapa','9845678954','male','1978-6-7','1994-1-3','ran5','Na11088905433');
Query OK, 1 row affected (0.17 sec)
MariaDB [armydetails]> select * from armydetails;
+-------+---------+---------+-----------+------------+--------+------------+------------+--------+----------------+
| regNo | fName | lName | address | number | gender | DOB | DOJ | rankID | accountNo |
+-------+---------+---------+-----------+------------+--------+------------+------------+--------+----------------+
| r05 | Shishir | Bhujel | Jhapa | 9845678954 | male | 1978-06-07 | 1994-01-03 | ran5 | Na11088905433 |
| ro1 | Milan | Katwal | Dharan | 9811095122 | Male | 1970-01-03 | 1990-01-01 | ran1 | Na11984567823 |
| ro2 | Hari | Yadav | Kathmandu | 9810756436 | male | 1980-06-07 | 2000-05-06 | ran2 | Na119876678543 |
| ro3 | Khrisna | Neupane | Itahari | 9864578934 | male | 1980-02-02 | 2001-01-07 | ran3 | Na11954437890 |
| ro4 | Lalit | Rai | Damak | 9842376547 | male | 1989-05-09 | 2005-01-02 | ran4 | Na11064553221 |
+-------+---------+---------+-----------+------------+--------+------------+------------+--------+----------------+
5 rows in set (0.00 sec)
MariaDB [armydetails]>
The SQL 2011 publication from ISO/IEC 9075 says:
In general, rows in a table are unordered; however, rows in a table are ordered if the table is the result of a that immediately contains an « order by clause ».
In a SQL database, there is no underlying, default ordering for records. A relational database basically stores a table as a bunch of unordered records.
When records are SELECTed without an ORDER BY clause, they come out in an undefined order, that in no way is guaranteed to be consistent over subsequent queries (including the very same query being executed several times). This is true for MySQL and for other RDBMS.
The only way to properly order records is to use an ORDER BY clause, like:
select * from armydetails order by regNo
Suggested lecture: Tom Kyte Blog : Order in the Court!.
You can simply add an ORDER BY clause to your statment as follows:
SELECT * FROM armydetails ORDER BY regNO DESC;
I want to select value from table sorted by a certain order.
I have a table called test that looks like this:
| date | code | value |
+----------+-----------+----------+
| 20050104 | 000005.SZ | -6359.19 |
| 20050104 | 600601.SH | -7876.34 |
| 20050104 | 600602.SH | -25693.3 |
| 20050104 | 600651.SH | NULL |
| 20050104 | 600652.SH | -15309.9 |
...
| 20050105 | 000005.SZ | -4276.28 |
| 20050105 | 600601.SH | -3214.56 |
...
| 20170405 | 000005.SZ | 23978.13 |
| 20170405 | 600601.SH | 32212.54 |
Right now I want to select only one date, say date = 20050104, and then sort the data by a certain order (the order that each stock was listed in the stock market).
I have another table called stock_code which stores the correct order:
+---------+-----------+
| code_id | code |
+---------+-----------+
| 1 | 000002.SZ |
| 2 | 000004.SZ |
| 3 | 600656.SH |
| 4 | 600651.SH |
| 5 | 600652.SH |
| 6 | 600653.SH |
| 7 | 600654.SH |
| 8 | 600602.SH |
| 9 | 600601.SH |
| 10 | 000005.SZ |
...
I want to sorted the selected data by stock_code(code_id), but I don't want to use join because it takes too much time. Any thoughts?
I tried to use field but it gives me an error, please tell me how to correct it or give me an even better idea.
select * from test
where date = 20050104 and code in (select code from stock_code order by code)
order by field(code, (select code from stock_code order by code));
Error Code: 1242. Subquery returns more than 1 row
You told us that you don't want to join because it takes too much time, but the following join query is probably the best option here:
SELECT t.*
FROM test t
INNER JOIN stock_code sc
ON t.code = sc.code
WHERE t.date = '20050104'
ORDER BY sc.code_id
If this really runs slowly, then you should check to make sure you have indices setup on the appropriate columns. In this case, indices on the code columns from both tables as well as an index on test.date should be very helpful.
ALTER TABLE test ADD INDEX code_idx (code)
ALTER TABLE test ADD INDEX date_idx (date)
ALTER TABLE code ADD INDEX code_idx (code)
I have an activities table like below (also contains some other columns):
+------------------+---------------+------------+
| data | event | logged_on |
+------------------+---------------+------------+
| 12345 | File | 2015-04-08 |
| 25232 | Bulletin | 2015-04-08 |
| 7890 | File | 2015-04-08 |
| youtube | Search | 2015-04-07 |
| 13568 | Bulletin | 2015-04-07 |
| 25232 | Bulletin | 2015-04-07 |
| 7890 | File | 2015-04-07 |
+------------------+---------------+------------+
I want to fetch unique data values for latest date. So the required result would be:
+------------------+---------------+------------+
| data | event | logged_on |
+------------------+---------------+------------+
| 12345 | File | 2015-04-08 |
| 25232 | Bulletin | 2015-04-08 |
| 7890 | File | 2015-04-08 |
| youtube | Search | 2015-04-07 |
| 13568 | Bulletin | 2015-04-07 |
+------------------+---------------+------------+
But a select distinct on all the three columns above returns the same value of data for different dates. I cannot remove logged_on from the select query as it's required elsewhere.
In MySQL, i tried using the following query:
SELECT DISTINCT
data,
event,
MAX(logged_on) AS latest_log_date
FROM
activites
WHERE
username = %%(username)s
GROUP BY
data
ORDER BY id DESC, latest_log_date DESC
LIMIT %%(limit)s
;
But this does not seem to work. I'm getting the some result, which looks like it's correct, but it isn't. And i'm not able to reason about it. Any ideas?
Use NOT EXISTS to return only rows that has no later with same data/event.
SELECT data, event, logged_on AS latest_log_date
from activites a1
where not exists (select 1 from activites a2
where a1.data = a2.data
and a1.event = a2.event
and a2.logged_on > a1.logged_on)
I'm not quite sure if this is what you want. Perhaps you need to remove and a1.event = a2.event from the sub-query.
SELECT data, event, logged_on
FROM activities A1
WHERE logged_on = (SELECT A2.logged_on FROM activities A2
WHERE A2.data = A1.data AND A2.event = A1.event
ORDER BY A2.logged_on DESC LIMIT 1);
Maybe i have not got your question clear, but this query is giving me your required output
select data,event,logged_on from activities group by data order by logged_on desc;
I'm trying to identify if a row has the value '1' anywhere in it (AKA any column). Is there an easy way to do this without searching every column with fetchrow_array? I've included a small table I've been working with as an example.
mysql> select * from Case_Tracking;
+--------------------+---------+---------+----------+---------+----------+---------------+
| accession_number | cyp2d6 | cyp2c19 | factorII | factorV | apoe | vkorc1_cyp2c9 |
+--------------------+---------+---------+----------+---------+----------+---------------+
| AIB14-1116-0000453 | Luminex | Luminex | Hologic | 1 | ABI 7500 | Genmark |
| AIB14-1123-0000074 | NULL | Luminex | Hologic | Hologic | ABI 7500 | Genmark |
+--------------------+---------+---------+----------+---------+----------+---------------+
It would be better to search every column using SQL (WHERE accession_number = '1' OR cyp2d6 = '1' OR ...) since you'd only need to fetch matching results.
I'm feeling a little rusty with creating queries in MySQL. I thought I could solve this, but I'm having no luck and searching around doesn't result in anything similar...
Basically, I have two tables. I want to select everything from one table and the matching row from the second table. However, I only want to have the first result from the second table. I hope that makes sense.
The rows in the daily_entries table are unique. There will be one row for each day, but maybe not everyday. The second table notes contains many rows, each of which are associated with ONE row from daily_entries.
Below are examples of my tables;
Table One
mysql> desc daily_entries;
+----------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+--------------+------+-----+---------+----------------+
| eid | int(11) | NO | PRI | NULL | auto_increment |
| date | date | NO | | NULL | |
| location | varchar(100) | NO | | NULL | |
+----------+--------------+------+-----+---------+----------------+
Table Two
mysql> desc notes;
+---------+---------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------+---------+------+-----+---------+----------------+
| task_id | int(11) | NO | PRI | NULL | auto_increment |
| eid | int(11) | NO | MUL | NULL | |
| notes | text | YES | | NULL | |
+---------+---------+------+-----+---------+----------------+
What I need to do, is select all entries from notes, with only one result from daily_entries.
Below is an example of how I want it to look:
+----------------------------------------------+---------+------------+----------+-----+
| notes | task_id | date | location | eid |
+----------------------------------------------+---------+------------+----------+-----+
| Another note | 3 | 2014-01-02 | Home | 2 |
| Enter a note. | 1 | 2014-01-01 | Away | 1 |
| This is a test note. To see what happens. | 2 | | Away | 1 |
| Testing another note | 4 | | Away | 1 |
+----------------------------------------------+---------+------------+----------+-----+
4 rows in set (0.00 sec)
Below is the query that I currently have:
SELECT notes.notes, notes.task_id, daily_entries.date, daily_entries.location, daily_entries.eid
FROM daily_entries
LEFT JOIN notes ON daily_entries.eid=notes.eid
ORDER BY daily_entries.date DESC
Below is an example of how it looks with my query:
+----------------------------------------------+---------+------------+----------+-----+
| notes | task_id | date | location | eid |
+----------------------------------------------+---------+------------+----------+-----+
| Another note | 3 | 2014-01-02 | Home | 2 |
| Enter a note. | 1 | 2014-01-01 | Away | 1 |
| This is a test note. To see what happens. | 2 | 2014-01-01 | Away | 1 |
| Testing another note | 4 | 2014-01-01 | Away | 1 |
+----------------------------------------------+---------+------------+----------+-----+
4 rows in set (0.00 sec)
At first I thought I could simply GROUP BY daily_entries.date, however that returned only the first row of each matching set. Can this even be done? I would greatly appreciate any help someone can offer. Using Limit at the end of my query obviously limited it to the value that I specified, but applied it to everything which was to be expected.
Basically, there's nothing wrong with your query. I believe it is exactly what you need because it is returning the data you want. You can not look at as if it is duplicating your daily_entries you should be looking at it as if it is return all notes with its associated daily_entry.
Of course, you can achieve what you described in your question (there's an answer already that solve this issue) but think twice before you do it because such nested queries will only add a lot of noticeable performance overhead to your database server.
I'd recommend to keep your query as simple as possible with one single LEFT JOIN (which is all you need) and then let consuming applications manipulate the data and present it the way they need to.
Use mysql's non-standard group by functionality:
SELECT n.notes, n.task_id, de.date, de.location, de.eid
FROM notes n
LEFT JOIN (select * from
(select * from daily_entries ORDER BY date DESC) x
group by eid) de ON de.eid = n.eid
You need to do these queries with explicit filtering for the last row. This example uses a join to do this:
SELECT n.notes, n.task_id, de.date, de.location, de.eid
FROM daily_entries de LEFT JOIN
notes n
ON de.eid = n.eid LEFT JOIN
(select n.eid, min(task_id) as min_task_id
from notes n
group by n.eid
) nmin
on n.task_id = nmin.min_task_id
ORDER BY de.date DESC;