My client has a set of numeric data stored in a string field in a database. So of course it doesn't sort correctly. These rows sort like this:
105
3
44
When they should sort like this:
3
44
105
This is very much a legacy database and I can't change it at all. I also can't change the software that uses the database. The client doesn't own it or have the source code. It has never worked the way they want. However, there is an unused string field that I could use to sort on (only a small number of fields can be sorted on.)
What I would like to do is take the input data, derive a string from it, and store the new string in the unused field, such that when the data is sorted on this new data, the original data sorts correctly, i.e., numerically.
So, for an overly simplistic example, if the algorithm produced the following new data:
105 -> c
3 -> a
44 -> b
Then when the second column was sorted, the first column would look 'correct'.
The tricky bit is that when new rows are added to the database, they must also sort correctly, without having to regenerate the sort data for all rows. This is the part of the problem that has my brain in a twist. I'm not sure it's actually possible.
You can assume that the number will never be more than 5 'digits'.
I realize this is a total kludge, but since I can't change the system, I have to find a work around, rather than a quality solution. Welcome to the real world.
~~~~~~~~~~~~~~~~~~~~~~ S O L U T I O N ~~~~~~~~~~~~~~~~~~
I don't think this is an uncommon problem, so here are the results of Gordon's solution:
mysql> select * from t order by new;
+------+------------+
| orig | new |
+------+------------+
| 3 | 0000000003 |
| 44 | 0000000044 |
| 105 | 0000000105 |
+------+------------+
In most databases, you can just do:
order by cast(col as int)
This will convert the string representation to a number and use that for ordering. There is no need for an additional column. If you add one, I would recommend adding a numeric column to contain the actual value.
If you really want to store something in the unused field, then you can left pad the number. How to do this depends on the database, but here is one typical method:
update t
set unused = right(concat('0000000000', col), 10);
Not all databases support these two specific functions, but all offer this basic functionality in some method.
Try something like
SELECT column1 FROM table1 ORDER BY LENGTH(column1) ASC, column1 ASC
(Adjust the column and table name for your environment.)
This is a bit of a hack but works as long as the "numbers" in your string column are natural, non-negative numbers only.
If you are looking for a more sophisticated approach or algorithm, try searching for natural sort together with your DBMS.
So we have a table with a field that contains strings.
These strings can contain wildcards.
For example:
id | name
---+----------------
1 | thomas
2 | san*
3 | *max*
Now I want to select from that table with respect to these wildcards.
For example something like this:
SELECT * FROM table WHERE name = 'sandra'.
That SELECT should fetch the record with ID = 2 from my table.
Note that it would be ok to use % instead of * as the wildcard character in the table.
Any way to achieve this in OpenSQL?
You can use wildcards, just the sign (like Matecki said), is %.
Take a look here:
https://scn.sap.com/thread/1418148
Additionally You could create and use a ranges table in the where clause. If You do not know, what it is, and how it can be done, just tell me. Populate the ranges table like this: OPTION = CP, SIGN = I, LOW = san.
Ok for You?
UPDATE:
I was wrong and changed the answer
i have string of value like "4,3,8"
and i had comma separated column in table as below.
ID | PrdID | cntrlIDs
1 | 1 | 4,8
2 | 2 | 3
3 | 3 | 3,4
4 | 4 | 5,6
5 | 5 | 10,14,18
i want only those records from above table which match in above mention string
eg.
1,2,3 this records will need in output because its match with the passing string of "4,3,8"
Note : i need this in entity framework LINQ Query.
string[] arrSearchFilter = "4,3,8".Split(',');
var query = (from prdtbl in ProductTables
where prdtbl.cntrlIDs.Split(',').Any(x=> arrSearchFilter.Contains(x))
but its not working and i got below error
LINQ to Entities does not recognize the method 'System.String[] Split(Char[])' method, and this method cannot be translated into a store expression.
LINQ to Entities tries to convert query expressions to SQL. String.Split is not one of the supported methods. See http://msdn.microsoft.com/en-us/library/vstudio/bb738534(v=vs.100).aspx
Assuming you are unable to redesign the database structure, you have to bypass the SQL filter and obtain ALL records and then apply the filter. You can do this by using ProductTables.ToList() and then using this in second query with the string split, e.g.
string[] arrSearchFilter = "4,3,8".Split(',');
var products = ProductTables.ToList();
var query = (from prdtbl in products
where prdtbl.cntrlIDs.Split(',').Any(x=> arrSearchFilter.Contains(x))
This is not a good idea if the Product table is large, as you are losing a key benefit of SQL and loading ALL the data before filtering.
Redesign
If that is a problem and you can change the database structure, you should create a child table that replaces the comma-separated values with a proper normalised structure. Comma separated variables might look like a convenient shortcut but they are not a good design and as you have found, are not easy to work with in SQL.
SQL
If the design cannot be changed and the table is large, then your only other option is to hand-roll the SQL and execute this directly, but this would lose some of the benefits of having Linq.
I have a query that produces a 2 field result: Email and Interest.
The result is millions of records. But there are about 100 distinct Interests.
I would like to run the query to produce a result that is 101 fields wide like this:
Email | Books | Cats | Dogs | ETC
Where the metric is the count of each.
With my knowledge of SQL thus far I'd have to use CASE WHEN. But I'd have to write 100 lines of code.
Is there a better way?
You could use the PIVOT statement but sounds like terradata does not support that. Pivot would require typing in all column names as well. Don't think you can avoid that
I've been beating my head on the desk trying to figure this one out. I have a table that stores job information, and reasons for a job not being completed. The reasons are numeric,01,02,03,etc. You can have two reasons for a pending job. If you select two reasons, they are stored in the same column, separated by a comma. This is an example from the JOBID table:
Job_Number User_Assigned PendingInfo
1 user1 01,02
There is another table named Pending, that stores what those values actually represent. 01=Not enough info, 02=Not enough time, 03=Waiting Review. Example:
Pending_Num PendingWord
01 Not Enough Info
02 Not Enough Time
What I'm trying to do is query the database to give me all the job numbers, users, pendinginfo, and pending reason. I can break out the first value, but can't figure out how to do the second. What my limited skills have so far:
select Job_number,user_assigned,SUBSTRING(pendinginfo,0,3),pendingword
from jobid,pending
where
SUBSTRING(pendinginfo,0,3)=pending.pending_num and
pendinginfo!='00,00' and
pendinginfo!='NULL'
What I would like to see for this example would be:
Job_Number User_Assigned PendingInfo PendingWord PendingInfo PendingWord
1 User1 01 Not Enough Info 02 Not Enough Time
Thanks in advance
You really shouldn't store multiple items in one column if your SQL is ever going to want to process them individually. The "SQL gymnastics" you have to perform in those cases are both ugly hacks and performance degraders.
The ideal solution is to split the individual items into separate columns and, for 3NF, move those columns to a separate table as rows if you really want to do it properly (but baby steps are probably okay if you're sure there will never be more than two reasons in the short-medium term).
Then your queries will be both simpler and faster.
However, if that's not an option, you can use the afore-mentioned SQL gymnastics to do something like:
where find ( ',' |fld| ',', ',02,' ) > 0
assuming your SQL dialect has a string search function (find in this case, but I think charindex for SQLServer).
This will ensure all sub-columns begin and start with a comma (comma plus field plus comma) and look for a specific desired value (with the commas on either side to ensure it's a full sub-column match).
If you can't control what the application puts in that column, I would opt for the DBA solution - DBA solutions are defined as those a DBA has to do to work around the inadequacies of their users :-).
Create two new columns in that table and make an insert/update trigger which will populate them with the two reasons that a user puts into the original column.
Then query those two new columns for specific values rather than trying to split apart the old column.
This means that the cost of splitting is only on row insert/update, not on _every single select`, amortising that cost efficiently.
Still, my answer is to re-do the schema. That will be the best way in the long term in terms of speed, readable queries and maintainability.
I hope you are just maintaining the code and it's not a brand new implementation.
Please consider to use a different approach using a support table like this:
JOBS TABLE
jobID | userID
--------------
1 | user13
2 | user32
3 | user44
--------------
PENDING TABLE
pendingID | pendingText
---------------------------
01 | Not Enough Info
02 | Not Enough Time
---------------------------
JOB_PENDING TABLE
jobID | pendingID
-----------------
1 | 01
1 | 02
2 | 01
3 | 03
3 | 01
-----------------
You can easily query this tables using JOIN or subqueries.
If you need retro-compatibility on your software you can add a view to reach this goal.
I have a tables like:
Events
---------
eventId int
eventTypeIds nvarchar(50)
...
EventTypes
--------------
eventTypeId
Description
...
Each Event can have multiple eventtypes specified.
All I do is write 2 procedures in my site code, not SQL code
One procedure converts the table field (eventTypeIds) value like "3,4,15,6" into a ViewState array, so I can use it any where in code.
This procedure does the opposite it collects any options your checked and converts it in
If changing the schema is an option (which it probably should be) shouldn't you implement a many-to-many relationship here so that you have a bridging table between the two items? That way, you would store the number and its wording in one table, jobs in another, and "failure reasons for jobs" in the bridging table...
Have a look at a similar question I answered here
;WITH Numbers AS
(
SELECT ROW_NUMBER() OVER(ORDER BY (SELECT 0)) AS N
FROM JobId
),
Split AS
(
SELECT JOB_NUMBER, USER_ASSIGNED, SUBSTRING(PENDING_INFO, Numbers.N, CHARINDEX(',', PENDING_INFO + ',', Numbers.N) - Numbers.N) AS PENDING_NUM
FROM JobId
JOIN Numbers ON Numbers.N <= DATALENGTH(PENDING_INFO) + 1
AND SUBSTRING(',' + PENDING_INFO, Numbers.N, 1) = ','
)
SELECT *
FROM Split JOIN Pending ON Split.PENDING_NUM = Pending.PENDING_NUM
The basic idea is that you have to multiply each row as many times as there are PENDING_NUMs. Then, extract the appropriate part of the string
While I agree with DBA perspective not to store multiple values in a single field it is doable, as bellow, practical for application logic and some performance issues. Let say you have 10000 user groups, each having average 1000 members. You may want to have a table user_groups with columns such as groupID and membersID. Your membersID column could be populated like this:
(',10,2001,20003,333,4520,') each number being a memberID, all separated with a comma. Add also a comma at the start and end of the data. Then your select would use like '%,someID,%'.
If you can not change your data ('01,02,03') or similar, let say you want rows containing 01 you still can use " select ... LIKE '01,%' OR '%,01' OR '%,01,%' " which will insure it match if at start, end or inside, while avoiding similar number (ie:101).