How do I update a table with fields selected from another table? - mysql

Although there are many questions similar to this, such as
"Updating a record from another table", but i could not get this working.
I have a query that selects and updates table sem_stdexamfinresmark. The select subquery returns multiple rows of data whose size may not be equal to the table being updated, but the update is now working.
The query looks like :
update sem_stdexamfinresmark sr,
(select
se.currsession,
str.studentid,
str.classid,
str.subjectid,
str.aggScore*(select gbtp.percentage from gb_termpercentage gbtp where gbtp.termname = se.examtype)/100 as aggPer,
str.aggGrade
from
sem_stdexamtermresr str,
sem_exam se
where
str.examid=se.examid and
se.examtype = 'Second Term' and
se.currsession =1 and classid='8'
) s
set
sr.SecondTermMark = s.aggPer and
sr.SecondTermGrade = s.aggGrade
where
sr.studentid=s.studentid and
sr.subjectid=s.subjectid and
s.currsession = s.currsession and
sr.classid='8';
EDIT:
update sem_stdexamfinresmark
set
sr.SecondTermMark = s.aggPer and
sr.SecondTermGrade = s.aggGrade
from
(select
se.currsession,
str.studentid,
str.classid,
str.subjectid,
str.aggScore*(select gbtp.percentage from gb_termpercentage gbtp where gbtp.termname = se.examtype)/100 as aggPer,
str.aggGrade
from
sem_stdexamtermresr str,
sem_exam se
where
str.examid=se.examid and
se.examtype = 'Second Term' and
se.currsession = 1 and classid='8'
) s
where
sr.studentid=s.studentid and
sr.subjectid=s.subjectid and
s.currsession =1 and
sr.classid='8';
select * from sem_exam;
update sem_exam set currsession =1;

try something that looks more like:
update foo
set col = bar.col
from bar
where ...

This is what happens when one loses sleep :( I just did a silly mistake here and added "and"

Related

MySQL update with sequential number yields NULL

I want to update the values of a column with the name of a related entry appended with a number for each row. I've seen a couple of other questions which give roughly the same answer, but when I try the below, I get NULL added instead.
SET #i = 0;
UPDATE matrix_data md
SET col_id_4 = concat((SELECT title from titles t WHERE t.entry_id = md.entry_id), (#i:=#i+1));
If I replace (#i:=#i+1) with a static value, then the update works OK.
The col_id_4 column is set to text. Does the above only work with numeric column types? And if so, how do I achieve what I want to do?
How about you take the primary key of the titles table instead of using the iterator, thus filling in col_id_4 with a concatenation of titles.title and titles.entry_id, thus…
UPDATE matrix_data
INNER JOIN titles ON matrix_data.entry_id = titles.entry_id
SET matrix_data.col_id_4 = CONCAT(titles.title, "_", titles.entry_id)
Or maybe it’s a type issue; casting the iterator to char(50) as we concatenate with the string should work. Tested in a rudimentary database, not #craftcms or #eecms specifically.
SET #i := 0;
UPDATE matrix_data
INNER JOIN titles ON matrix_data.entry_id = titles.entry_id
SET matrix_data.col_id_4 = CONCAT(titles.title, "_", CAST(#i := #i + 1 as CHAR(50)))

Can't update two tables in one Query

I've got two Queries to Update two tables:
First Table
UPDATE user_info SET `location` = ".$locationid.", `looking_for` = ".$lookingfor." WHERE `user_info`.`user_id` = ".$infoid.";
Second Table
UPDATE user_personality SET `personality` = '".$changedescription."' WHERE `user_personality`.`user_info_id` = ".$infoid.";
And I'm trying to merge those two Queries, using the same statement.
UPDATE user_info, user_personality
SET user_info.location = ".$locationid.", user_info.`looking_for` = ".$lookingfor.", user_personality.personality = '".$changedescription."'
WHERE `user_info`.`user_id` = ".$infoid."
AND `user_personality`.`user_info_id` = ".$infoid."
I'm not receiving any error message, but is not updating.
What am I doing wrong?
Thanks.
Just a guess...
"
UPDATE user_info i
JOIN user_personality p
ON p.user_info_id = i.user_id
SET i.location = $locationid
, i.looking_for = '$lookingfor'
, p.personality = '$changedescription'
WHERE i.user_id = $infoid;
";
If you set the 2 table fields equal to each other in the where clause it should work, so I believe you'd change your where clause to:
WHERE `user_info`.`user_id` = `user_personality`.`user_info_id`
AND `user_info`.`user_id` = ".$infoid."
MySQL definitely supports updating multiple tables, so the where clause that works for a multi table select statement should also work for an update.

Update SQL records with values from another record

I'm spinning in circles trying to figure out what is likely a very simple SQL structure. My task seems simple - within the same table I need to update 3 related records with data from one master record. The master coordinates are in the record with a class of 'T', and I want to insert that record's coordinates into the rx_latitude/longitude columns of the related records with class code 'R'
The table structure is: callsign, class, tx_latitude, tx_longitude, rx_latitude, rx_longitude. Sample data looks like this:
J877, T, 40.01, -75.01, 0, 0
J877, R, 39.51, -75.21, 0, 0
J877, R, 40.25, -75.41, 0, 0
J877, R, 39.77, -75.61, 0, 0
Within that same table, I want to populate all of the rx_latitude and rx_longitude fields where the class is 'R' with the tx_latitude and tx_longitude coordinates where the class is 'T' and the callsign matches.
I've tried several insert and update statements, but I can only seem to operate on the master record, not the related records. I would appreciate any guidance that you might offer.
You can use UPDATE...FROM statement:
UPDATE theTable
SET
tx_latitude = masterRecord.tx_latitude,
tx_longitude = masterRecord.tx_longitude
FROM
(SELECT tx_latitude,tx_longitude,callsign FROM theTable WHERE class='T') masterRecord
WHERE
class='R' AND callsign = masterRecord.callsign
Updated
Try :
update yourTable t1, yourTable t2 set
t1.tx_latitude = t2.tx_latitude,
t1.tx_longitude = t2.tx_longitude
where t1.class = 'R' and t2.class = 'T' and t1.callsign = t2.callsign
Example
You can use MySQL's update ... join syntax.
It would go something like this:
update yourtable toUpdate
left join yourtable masterRecordTable
on toUpdate.callsign = masterRecordTable.callsign and masterRecordTable.class = 'T'
set toUpdate.rx_latitude = masterRecordTable.tx_latitude,
toUpdate.rx_longitude = masterRecordTable.tx_longitude
where toUpdate.callsign = 'J877' and toUpdate.class = 'R'
See this fiddle for a working example

Update table using alias

I need to fill some fields in a table getting informations from other records of the same table.
I tried to write a query to explain what I want to do:
update globale2
set
nita = t.nita,
tita = t.tita,
notaita = t.notaita
where
neng = t.neng and
nita is null
(select nita, neng, tita, notaita from globale where uris='mma' and nita is not null) as t
edit to eplain better:
every records have these fields: "nita", "tita", "notaita", "neng" ("neng" cannot be null)
I want to fill these fields: "nita", "tita", "notaita" (where "nita" is empty)
with the same values from another record where "neng" equals the other "neng"
You can however, join the two tables.
UPDATE globale2 g
INNER JOIN globale gg
ON g.neng = gg.neng
SET g.nita = gg.nita,
g.tita = gg.tita,
g.notaita = gg.notaita
WHERE g.nita IS NULL
AND gg.uris = 'mma'
AND gg.nita IS NOT NULL
assume there is a table A_temp, with two columns 'one' and 'two'.
TABLE A_temp
ONE TWO
1 2
this is the present status of the table.
The query
UPDATE (SELECT * FROM A_temp ) A SET one = A.two where one = '1'
updates the table as
ONE TWO
2 2
Hope you get the idea and that it helps..

Complex MySQL query issue

I have a somewhat complex mySQL query I am trying to execute. I have two parameters: facility and isEnabled. Facility can have a value of "ALL" or be specific ID. isEnabled can have value of "ALL" or be 0/1.
My issue is that I need to come up with logic that can handle the following scenarios:
1) Facility = ALL AND isEnabled = ALL
2) Facility = ALL AND isEnabled = value
3) Facility = someID AND isEnabled = ALL
4) Facility = someID AND isEnabled = value
The problem is that I have several nested IF statements:
IF (Facility = 'ALL') THEN
IF (isEnabled = 'ALL') THEN
SELECT * FROM myTable
ELSE
SELECT * FROM myTable
WHERE isEnabled = value
END IF;
ELSE
IF (isEnabled = 'ALL') THEN
SELECT * FROM myTable
WHERE facility = someID
ELSE
SELECT * FROM myTable
WHERE facility = someID AND isEnabled = value
END IF;
END IF;
I would like to be able to combine the logic in the WHERE clause using either a CASE statement or Conditional's (AND/OR) but I am having trouble wrapping my head around it this morning. Currently the query is not performing as it is expected to be.
Any insight would be helpful!
Thanks
You could do this...
SELECT
*
FROM
myTable
WHERE
1=1
AND (facility = someID OR Facility = 'ALL')
AND (isEnabled = value OR isEnabled = 'ALL')
However, this yields a poor execution plan - it's trying to find one size fits all, but each combination of parameters can have different plans depending on data, indexes, etc.
This means that it is better to build the query dynamically
SELECT
*
FROM
myTable
WHERE
1=1
AND facility = someID -- Only include this line if : Facility = 'ALL'
AND isEnabled = value -- Only include this line if : isEnabled = 'ALL'
I know it can feel dirty to use dynamic queries, but this is a good corner case as to when then really can excel. I'll go find a spectacularly informative link for you now. (It's a lot to read, but it's very worth learning from)
Link : Dynamic Search