I've got a database with a column that contains the following data:
aaa-1
aaa-2
aaa-3
...
aaa-10
aaa-11
...
aaa-100
aaa-101
...
aaa-1000
When I query and sort the data in ascending order, I get:
aaa-1
aaa-10
aaa-11
...
aaa-100
aaa-101
...
aaa-1000
...
aaa-2
...
aaa-3
Is this actually the correct (machine) way of sorting? Is the order being screwed up because of the aaa- prefix? How do I go about sorting this the way a human would (ie something that looks like the first snippet)?
P.S. If the problem does lie in the prefix, is there a way to remove it and sort with just the numeric component?
P.P.S. It's been suggested to me that I should just change my data and add leading zeroes like aaa-0001 and aaa-0002, etc. However, I'm loathe to go that method as each time the list goes up an order of 10, I'd have to reformat this column.
Thank you all in advance! :)
You can extract the number part, convert it to numeric data type and then do an ORDER BY:
SELECT mytable.*,
CAST(SUBSTRING_INDEX(mycolumn, '-', - 1) AS UNSIGNED) mycolumnintdata
FROM
mytable
ORDER BY mycolumnintdata;
If there are expressions which does not match number, the CAST function would return 0 and those records would be displayed first. You may handle this separately if needed.
I had a similar issue and the trick that did it for me was this one
*"ORDER BY LENGTH(column_name), column_name
As long as the non-numeric part of the value is the same length, this will sort 1 before 10, 10 before 100, etc."*
as given by Andreas Bergström on this question.
Hope that helps someone.
this is the alphabetical order,
you want numerical order,
for do this you must in the ORDER BY clause
trim the costant "aaa-" part
convert it in number
convert(SUBSTRING(val, 3), integer)
I will give you a sample sorting. Not based on your data sample, but this could help you out.
Say you have data like this :
id
----
1
2
6
10
13
when you do ORDER BY id ASC would return :
id
----
1
10
13
2
6
I suggest, use LPAD.
This query : SELECT LPAD('12',5,'0') return 00012
So when you have table data like I provide above, you can sort them like this :
SELECT * FROM TABLE
ORDER BY LPAD(ID,7,'0') ASC
Based on your data.
SELECT SUBSTR('aaa-100',5,LENGTH('aaa-100') - 3) return 100
So, SELECT LPAD( SUBSTR('aaa-100',5,LENGTH('aaa-100') - 3), 7, '0') return 00000100
So you can combine string function such as SUBSTR and LPAD. Do have any clue now?
Related
I have a table in mysql. Table Name is constitutive_table, it contains more than 40 columns and its type is varchar, it contains more than 25000 records. I wrote the query like this to get the 10 least value. But it showing like as you have seen in the picture.
SELECT `Sequence_Name`
, `Name_of_the_Protein`
, `Brain`
FROM `constitutive_table`
where `Brain` != 0
ORDER
BY cast(Brain AS int)
LIMIT 0,10
The data in the Brain column appears to be floating point, so you should be casting to the appropriate type:
SELECT Sequence_Name, Name_of_the_Protein, Brain
FROM constitutive_table
WHERE CAST(Brain AS DECIMAL(14, 8)) <> 0
ORDER BY CAST(Brain AS DECIMAL(14, 8))
LIMIT 10
Most likely what is happening now is that the 10 values you see all have the same value when cast to integer. As a result, MySQL is using some secondary sort to generate the order you do see.
While the above query may resolve your problem, ideally you should change the Brain column to some numeric type.
Current SQL: SELECT code FROM myTable ORDER BY code ASC
code
---
11
113
12
13A
This is the current order I have of a MySQL table.
I want the order to be A-Z, 1-10 however, numerically, like this:
code
---
11
12
13A
113
The reason I cannot achieve this effect in the first place is because the code column is varchar and not int. However as shown in the example, some codes have a letter prepended to them so I cannot change this to integer.
How can I get around this problem without changing the data type?
The simplest way is to use silent conversion. Just add 0:
order by code + 0
In practice, you might want:
order by code + 0, code
This should work, sorting by number first and alpha after (if the same number):
select * from myTable
order by cast(replace(code,'[0-9]+','') as unsigned), code
See this SQL Fiddle
my id or primary key is and the data type of is VARCHAR(50)
0.0.01
0.0.100
0.0.101
0.0.1011
0.0.201
0.0.501
0.0.99
0.0.999
0.01.0
0.01.10
0.02.10
0.02.20
0.02.99
01.0.0
01.0.99
01.02.99
01.03.444
01.05.88
10.02.99
100.100.100
25.45.1001
99.99.99
I have to get it in sorted order
so i tried this
select id from table order by cast(id as decimal) desc;
but it does not work
the expected order is after running the query
0.0.01
0.0.99
0.0.100
0.0.101
0.0.201
0.0.501
0.0.999
0.0.1011
0.01.0
0.01.10
0.02.10
0.02.20
0.02.99
01.0.0
01.0.99
01.02.99
01.03.444
01.05.88
10.02.99
25.45.1001
99.99.99
100.100.100
i am using mysql for this
Not an easier one but you can use substring_index for each decimal places
select *
from t
order by
substring_index(id,'.',1) * 1,
substring_index(substring_index(id,'.',-2),'.',1) * 1,
substring_index(id,'.',-1) * 1
Explanation
I have use substring_index what it does it will return the piece of string in provided column like in above case i have use id column by the occurrence of delimiter i.e(.) for example a string like 0.1.2 for above 3 sunstring_index usage will return as below
substring_index('0.1.2','.',1) will give result as 0
substring_index(substring_index('0.1.2','.',-2),'.',1) will give result as 1
substring_index('0.1.2','.',-1) will give result as 2
For type casting to number i have multiplied the result of substring_index to 1 so the order by expression will first order the results by the number before first dot then with number before second dot and last the number after second dot in ascending manner
Demo
Sources:
http://www.w3resource.com/mysql/string-functions/mysql-substring_index-function.php
Your ID column has invalid decimal value so casting could not work here.
Try without casting this should work:
select id from table order by id desc;
DEMO
I have a column (of VARCHAR type) with values like these:
1
2
3
1.1
1.1.1
1.2.1
5
4
7
8
9
10
10.2
10.1
I hop[e to select this column and order it naturally, like the following:
1
1.1
1.1.1
1.2.1
2
3
4
5
...
I have tried ordering it with this for example and a lot of other query
SELECT data
FROM sample
ORDER BY LEN(data), data
Does someone have an idea how to do this?
try this
ORDER BY data, LEN(data)
or this
ORDER BY CONVERT(SUBSTRING_INDEX(data, ',', -1), SIGNED), Len(data)
i give demo in mysql as tsql there is not in sqfiddle .
DEMO
You seem to be hoping to order a series of hierarchically named items in a natural order. It looks like these items' names take the form.
token [ .token [. token [ .token ]]]
where subsequent tokens after the first are optional.
I suppose you want each token, if it's numeric, to be handed as a number. That is, for example, you want 1.123 to come after 1.2 because 123 is numerically greater than 2.
You didn't say what you want done with alphabetical tokens, e.g. 401.k and 403.b. I suppose they should come after the numerical ones, but in lexical order.
This query (http://sqlfiddle.com/#!2/81756/2/0) will do the trick out to five hierarchical levels of tokens.
SELECT col
FROM T
ORDER BY
FLOOR(SUBSTRING_INDEX(col,'.',1)),
SUBSTRING_INDEX(col,'.',1),
FLOOR(SUBSTRING(col, 2+LENGTH(SUBSTRING_INDEX(col,'.',1)))),
SUBSTRING(col, 2+LENGTH(SUBSTRING_INDEX(col,'.',1))),
FLOOR(SUBSTRING(col, 2+LENGTH(SUBSTRING_INDEX(col,'.',2)))),
SUBSTRING(col, 2+LENGTH(SUBSTRING_INDEX(col,'.',2))),
FLOOR(SUBSTRING(col, 2+LENGTH(SUBSTRING_INDEX(col,'.',3)))),
SUBSTRING(col, 2+LENGTH(SUBSTRING_INDEX(col,'.',3))),
FLOOR(SUBSTRING(col, 2+LENGTH(SUBSTRING_INDEX(col,'.',4)))),
SUBSTRING(col, 2+LENGTH(SUBSTRING_INDEX(col,'.',4)))
Why does this work? FLOOR() converts the leftmost part of a string to an integer, so it picks up the leading integer. If it doesn't find any numbers in the string it's trying to convert, it returns zero.
And, SUBSTRING(col, 2+LENGTH(SUBSTRING_INDEX(col,'.',NNN))) picks up the part of the col item to the right of the NNNth dot.
The data seems something like Hierarchical. With the current set of data supplied, if data is converted to hierarchical Data the order by can be done using something similar to:-
SELECT data FROM sample ORDER BY CAST ( '/' + replace( data, '.',
'/' ) + '/' as hierarchyid )
Hi I want to sort a table .The field contains numbers,alphabets and numbers with alphabets ie,
1
2
1a
11a
a
6a
b
I want to sort this to,
1
1a
2
6a
11a
a
b
My code is, SELECT * FROM t ORDER BY CAST(st AS SIGNED), st
But the result is,
a
b
1
1a
2
6a
11a
I found this code in this url "http://www.mpopp.net/2006/06/sorting-of-numeric-values-mixed-with-alphanumeric-values/"
Anyone please help me
This would do your required sort order, even in the presence of 0 in the table;
SELECT * FROM t
ORDER BY
st REGEXP '^[[:alpha:]].*',
st+0,
st
An SQLfiddle to test with.
As a first sort criteria, it sorts anything that starts with a letter after anything that doesn't. That's what the regexp does.
As a second sort criteria it sorts by the numerical value the string starts with (st+0 adds 0 to the numerical part the string starts with and returns an int)
As a last resort, it sorts by the string itself to get the alphabetical ones in order.
You can use this:
SELECT *
FROM t
ORDER BY
st+0=0, st+0, st
Using st+0 the varchar column will be casted to int. Ordering by st+0=0 will put alphanumeric rows at the bottom (st+0=0 will be 1 if the string starts with an alphanumeric character, oterwise it will be 0)
Please see fiddle here.
The reason that you are getting this output is that all the character like 'a', 'b' etc are converted to '0' and if you use order by ASC it will appear at the top.
SELECT CAST(number AS SIGNED) from tbl
is returning
1
2
1
11
0
6
0
Look at this fiddle:- SQL FIDDLE
I did small change in your query -
SELECT *, CAST(st AS SIGNED) as casted_column
FROM t
ORDER BY casted_column ASC, st ASC
this should work.
in theory your syntax should work but not sure why mysql doesn't accept these methods after from tag.
so created temp field and then sorted that one .
This should work as per my experience, and you can check it.
SQL FIDDLE