I am trying to select a number of rows in a table, reverse the values in one column and reinsert them into the table. Here is an example of what I am doing, say I have the following data:
+-------+--------+-------+
| ORDER | X | Y |
+-------+--------+-------+
| 0 | 12 | 5 |
| 1 | 16 | 3 |
| 2 | 19 | 2 |
+-------+--------+-------+
I want to select it and reinsert it into the same table with the ORDER reversed as so:
+--------+--------+-------+
| PORDER | X | Y |
+--------+--------+-------+
| 2 | 12 | 5 |
| 1 | 16 | 3 |
| 0 | 19 | 2 |
+--------+--------+-------+
I am able to duplicate the rows and reinsert them, no problem using an insert ... select like this:
INSERT INTO myTable (porder, x, y) SELECT porder, x, y FROM myTable
but I have had no success reversing the order. I have tried
INSERT INTO myTable (porder, x, y) SELECT (SELECT porder FROM myTable ORDER BY porder DESC), x, y FROM myTable but that throws an error
It would be fine to simply ignore the porder column and insert new values from 0 to the highest number in the sequence (2 in my above example) but I don't know how to add sequential numbers in a multiple-row insert statement in mysql.
I know how to do this with php but I was thinking there must be a more elegant solution in just SQL
If you know the max-value of order, you can simply do (assuming max(order) = 2)
UPDATE `myTable` SET `PORDER` = 2 - `PORDER`
Example:
+--------+------------+
| PORDER | 2 - PORDER |
+--------+------------+
| 0 | 2-0 = 2 |
| 1 | 2-1 = 1 |
| 2 | 2-2 = 0 |
+--------+------------+
try this
INSERT INTO myTable(`porder`, x, y) SELECT (SELECT MAX(`porder`) FROM myTable) - `porder`, x, y FROM myTable
Related
I have a table like so (after doing a query on it to order it by score):
+---+-------+------+
|id | level |score |
+---+-------+------+
| 4 | 1 | 30 |
| 3 | 1 | 35 |
| 1 | 1 | 40 |
| 5 | 1 | 45 |
| 7 | 1 | 50 |
| 8 | 1 | 55 |
+---+-------+------+
I will output that to php in a while loop. So each row in the while loop will be the same as in the table above.
Essentially what I want to do is show 5 of these rows in a table (in html), with a certain row (e.g. where id=5) in the middle and have the two rows above and below it (in the correct order). This will be like a score board but only showing the user's score with the two above and two below.
E.g. say the user is id=5, I want to show
+---+-------+------+
|id | level |score |
+---+-------+------+
| 3 | 1 | 35 |
| 1 | 1 | 40 |
| 5 | 1 | 45 |
| 7 | 1 | 50 |
| 8 | 1 | 55 |
I am wondering does anyone know a way of doing this in php?
Basically
//select query output is in while loop
//get a certain row of the loop
//get the two rows above it and two rows below it
One method uses a lot of variables:
select t.*
from (select t.*,
lag(id, 1) over (order by score) as prev_id,
lag(id, 2) over (order by score) as prev_id2,
lead(id, 1) over (order by score) as next_id,
lead(id, 2) over (order by score) as next_id2
from t
) t
where 5 in (prev_id, prev_id2, next_id, next_id2, id)
order by score;
An alternative method is something like this:
(select t.*
from t
where t.score <= (select t2.score from t t2 where t2.id = 5)
order by score desc
limit 3
) union all
(select t.*
from t
where t.score > (select t2.score from t t2 where t2.id = 5)
order by score
limit 2
)
order by score;
This exactly syntax may not work in all databases, but the idea can easily be translated in whatever dialect of SQL. This also assumes that the scores are unique.
i already done everything to remove this duplicity on the database
On selecting a checkbox on the sectio "Bairros" i utilized as Array
for($m=0; $m<count($_POST["bairros"]); $m++){// LOOP 1
$pesquisar=($_POST["bairros"][$m]);
//Copy bairros(Array) and esporte (POST)
$query = "SELECT DISTINCT * FROM cadastro WHERE
(esporte1 = '".$_POST["esportes"]."' OR
esporte2 = '".$_POST["esportes"]."' OR
esporte3 = '".$_POST["esportes"]."' OR
esporte4 = '".$_POST["esportes"]."')
AND
(bairro1 = '".$pesquisar."' OR
bairro2 = '".$pesquisar."' OR
bairro3 = '".$pesquisar."' OR
bairro4 = '".$pesquisar."')
AND
ativarAparecer='sim' ORDER BY nomeCompleto ASC LIMIT 20";
$esporte= new consultar();
$esporte->executa($query);
//Loops
for($l=0; $l<$esporte->nrw; $l++){ //LOOP 2
echo $esporte->data["nomeCompleto"]."<br />";
$esporte->proximo();
} //close LOOP2
} //close LOOP1
Detail: this function object oriented, I believe that i'm doing something wrong at SQL or MYSQL, perhaps something is missing there.
SELECT DISTINCT *
Stop There. DISTINCT * can do what? Duplicate of what? it cant do that. Give it a field name to see unique values.
For example
SELECT DISTINCT nomeCompleto
Let's break this down. The DISTINCT clause will return unique sets based on the selected columns.
Let's say you have a table:
a | b | c
=========
1 | 2 | 3
1 | 1 | 3
1 | 2 | 4
Now if you SELECT DISTINCT a FROM table, you would get:
1
but if you SELECT DISTINCT a, b FROM table, you would get:
a | b
=====
1 | 2
1 | 1
That's because {1,2} is different from {1,1}, even though the a column is the same between those two sets.
Obviously, doing SELECT DISTINCT * FROM table would give you the original table because it uses all three columns as a "composition" of the unique set. If we amended the table to look like this:
a | b | c
=========
1 | 2 | 3
1 | 1 | 3
1 | 2 | 4
1 | 2 | 3
Then your result of SELECT DISTINCT * FROM table would give:
a | b | c
=========
1 | 2 | 3
1 | 1 | 3
1 | 2 | 4
because of the duplicate result set of {1, 2, 3}. However, since most tables have an auto-incrementing identifier as the primary key, there is almost always no difference between SELECT * and SELECT DISTINCT *.
Perhaps you're looking to GROUP BY a certain column?
How would I be using GROUP this in my script? Column that there are several equal records are this bairro, bairro2, bairro3, bairro4. Inside it is in numbers
bairro1 | bairro2 | bairro3 | bairro4
14 | 14 | 15 | 27
34 | 15 | 14 | 30
27 | 45 | 12 | 14
i have a table temporary as follow as:
student | Data | number
-----------|---------------|--------------
1 | book | 2
1 | book | 5
1 | book | 9
2 | book | 1
2 | book | 5
i will show reduction of column in like as output column as follow as:
student | Data | number |output (number column of next row-previous line )
-----------|---------------|----------------|--------------
1 | book | 2 | 0
1 | book | 5 | 3 (result of (5-2=3)
1 | book | 9 | 4 (result of (9-5=4)
2 | book | 1 | 0
2 | book | 5 | 4 (result of (5-1=4)
how are writing of php's script is correct? because i'm confused
You didn't mention your DBMS, so this is standard SQL:
select student,
data,
number,
number - lag(number,1,number) over (partition by student order by id) as output
from the_table
order by student, id
SQLFiddle example
The following script will subtract the number from previous number for the same student. Here's how you can do it in MySQL (which doesn't support window functions.)
SELECT
t1.student,
t1.Data,
t1.number,
IF (t2.number IS NULL, 0, t1.number - MAX(t2.number)) as output
FROM
tbl t1
LEFT JOIN
tbl t2
ON
t1.student = t2.student
AND t1.number > t2.number
GROUP BY
t1.student, t1.Data, t1.number
Here's the SQL Fiddle
I have table :
==========================================================
|id | before | after | freq | id_sentence | document_id |
==========================================================
| 1 | a | b | 1 | 0 | 1 |
| 2 | c | d | 1 | 1 | 1 |
| 3 | e | f | 1 | 1 | 1 |
| 4 | g | h | 2 | 0 | 2 |
==========================================================
I want to get the number of data depend on the id_sentence and freq so the result must be 1 2 1
here's the code :
$query = mysql_query("SELECT freq FROM tb where document_id='$doc_id' ");
while ($row = mysql_fetch_array($query)) {
$stem_freq = $row['freq'];
$total = $total+$stem_freq;
but the result is still wrong. please, help me.. thank you :)
If I understand your question, you are trying the calculate the sum of freq for each distinct id_sentence for a particular document_id.
Try the following SQL:
SELECT id_sentence, SUM(freq) as freq FROM tb WHERE document_id = 1 GROUP BY(id_sentence)
The result will be rows of data with the id_sentence and corresponding total freq. No need to manually sum things up afterwards.
See this SQL Fiddle: http://sqlfiddle.com/#!2/691ed/8
I think you could do something like
SELECT count(*) AS count FROM tb GROUP BY(id_sentence,freq)
to do the counting you want. You could even do something like
SELECT count(*) AS count, id_sentence, freq FROM tb GROUP BY(id_sentence,freq)
to know which id_sentence,freq combination the count is for.
I need to filter only these table rows which have same values in x and y columns.
_______________________________________
|
| x | y | name |
________________________________________
|
| 1 | 2 | A |
|______________________________________
| 2 | 1 | B |
|______________________________________
| 1 | 2 | C |
|_______________________________________
The final result should be that I have A and C result. I need to filter these rows which has identical x and y values.
_______________________________________
|
| x | y | name |
________________________________________
|
| 1 | 2 | A |
|______________________________________
______________________________________
| 1 | 2 | C |
|_______________________________________
I' ve tried this code but I only managed to with one field.
select *
from auto
where x in (
select x
from auto
group by x
having count(*) > 1
);
SELECT t1.*
FROM tablename t1, tablename t2
WHERE t1.x = t2.x
AND t1.y = t2.y
AND t1.primary_key != t2.primary_key
select * from
auto a, ( SELECT x, y, COUNT(*) FROM auto GROUP BY x, y HAVING COUNT(*) > 1 ) b
where a.x = b.x
and a.y = b.y
will mark your other question as duplicate