I have a table 'MyTable' which has some business logics. This table has a column called Expression which has a string built using other columns.
My query is
Select Value from MyTable where #Parameters_Built like Expression
The variable #Parameters_Built is built from Input parameters by Concatenating all together.
In my current scenario,
#Parameteres_Built='1|2|Computer IT/Game Design & Dev (BS)|0|1011A|1|0|'
Below are the expressions
---------------------
%%|%%|%%|0|%%|%%|0|
---------------------
1|2|%%|0|%%|%%|0|
---------------------
1|%%|%%|0|%%|%%|0|
---------------------
So my above query returns true for all the three rows. But It should return only the second row (Maximum match).
I just don't need a solution with fix for this scenario. It's just a example. I need a solution like choosing the best match. Any idea?
Try:
Select top 1 * from MyTable
where #Parameters_Built like Expression
order by len(Expression)-len(replace(Expression,'%',''))
- this orders the results by the number of non-% characters in expression.
SQLFiddle here.
Related
I have table with data like this:
Id | StringValue
----+-------------
1 | 4,50
2 | 90,40
I will get input StringValue like 4. I need to fetch the data exact matched record. When I am using LIKE operator, select query is returning two rows, but I need exact matched data record only.
Can anybody please help me with this?
SELECT *
FROM Table1
WHERE StringValue like '%4%'
But that returns two rows - both ID 1 and 2.
My expectation is I need to get ID = 1 row only
Storing delimited data like this is a well documented anti-pattern, violates basic normalisation principles and prevents the database engine from fully utilising an index.
What you can do is delimit your search value and also ensure the expression to search is correctly delimited; this is an unsargable expression however and the strorage engine will have to scan all rows every time -
declare #valueToFind varchar(10) = '4';
select *
from t
where Concat(',', t.StringValue, ',') like Concat('%,' #valueToFind, ',%');
for SQL Server 2016 and later you can use STRING_SPLIT or earlier version of SQL Server, there are many alternative, just do a search for it.
Or, you can simply do
SELECT * FROM Table1 where ',' + StringValue + ',' like '%,4,%'
Table contains data as below
Table Name is REGISTER
Column Name is EXAM_CODE
Values like ('S6TJ','S7','S26','S24')
I want answer like below
Result set - > (6,7,26,24)
Please suggest solution - since regexp_replace is not recognized built in function name in SQL.
The complexity of the answer depends on two things: the RDBMS used and whether the numbers in the EXAM_CODE are contiguous.
I have assumed that the RDBMS is SQL Server and the numbers in EXAM_CODE are always contiguous. If not, please advise and I can revise the answer.
The following SQL shows a way of accomplishing the above using PATINDEX.:
CREATE TABLE #REGISTER (EXAM_CODE VARCHAR(10));
INSERT INTO #REGISTER VALUES ('S6TJ'),('S7'),('S26'),('S24');
SELECT LEFT(EXAM_CODE, PATINDEX('%[^0-9]%', EXAM_CODE) - 1)
FROM (
SELECT RIGHT(EXAM_CODE, LEN(EXAM_CODE) - PATINDEX('%[0-9]%', EXAM_CODE) + 1) + 'A' AS EXAM_CODE
FROM #REGISTER
) a
DROP TABLE #REGISTER
This outputs:
6
7
26
24
PATINDEX matches a specified pattern against a string (or returns 0 if there is no match).
Using this, the inner query fetches all of the string AFTER the first occurence of a number. The outer query then strips any text that may appear on the end of the string.
Note: The character A is appended to the result of the inner query in order to ensure that the PATINDEX check in the outer query will make a match. Otherwise, PATINDEX would return 0 and an error would occur.
I would like to ask if it is possible to do this:
For example the search string is '009' -> (consider the digits as string)
is it possible to have a query that will return any occurrences of this on the database not considering the order.
for this example it will return
'009'
'090'
'900'
given these exists on the database. thanks!!!!
Use the Like operator.
For Example :-
SELECT Marks FROM Report WHERE Marks LIKE '%009%' OR '%090%' OR '%900%'
Split the string into individual characters, select all rows containing the first character and put them in a temporary table, then select all rows from the temporary table that contain the second character and put these in a temporary table, then select all rows from that temporary table that contain the third character.
Of course, there are probably many ways to optimize this, but I see no reason why it would not be possible to make a query like that work.
It can not be achieved in a straight forward way as there is no sort() function for a particular value like there is lower(), upper() functions.
But there is some workarounds like -
Suppose you are running query for COL A, maintain another column SORTED_A where from application level you keep the sorted value of COL A
Then when you execute query - sort the searchToken and run select query with matching sorted searchToken with the SORTED_A column
How can I force SQL Server to Evaluate a sub query first?
My query looks something like:
SELECT ObjectId FROM
(SELECT ObjectId FROM Table Where Id = #Id) T
WHERE fn_LongRunningFunction(T.ObjectId) = 1
I want the outer where clause to evaluate on the result of the inner query. How would I do this without inserting the sub query into a temp table.
When I execute this query SQL evaluates the query as if it where written like:
SELECT ObjectId FROM Table Where Id = #Id AND fn_LongRunningFunction(ObjectId) = 1
which is not what I want.
Why you're even using a sub-query here you could have simply used one query here something like ....
SELECT ObjectId
FROM Table
Where Id = #Id
AND fn_LongRunningFunction(ObjectId) = 1
Note
Using a scalar function in where clause as you have will cause a full table scan, Since sql server has to touch every row in the column and execute the function on ObjectId column values to evaluate if it is equal to 1 or not.
Avoid using any functions in where clauses on column names whenever possible.
for example if you are evaluating a value of a column against a given value do the reverse on the other side of the comparison operator and leave the column alone in where clause, for example if you are looking for values in a table
WHERE ColumnName + 20 < 100
Instead of doing you could do something like
WHERE ColumnName < 100 -20
In first example sql server will have to touch every row and will add 20 to its value to evaluate it against 100 which will cause a table scan.
In 2nd example if sql server has an index on that column it will simply do a seek to see which values are less then 100 -20.
I have table with 3 columns. One is Id, second column is Name and the third one Description. How can I select the value in the Description field by giving the column index, 3?
Thanks in advance
You can't, from plain SQL (other than in the ORDER BY clause, which won't give you the value but will allow you to sort the result set by it).
If you are using another programming language to construct a dynamic query, you could use that to identify the column being selected by its index number.
Alternatively, you could parameterise your query to return a specific column based on a case statement - like so:
select a, b, c, d, e, ...,
case ?
when 1 then a
when 2 then b
when 3 then c
when 4 then d
when 5 then e
...
end as parameterised_column
from ...
The problem with referring to a column by an index number is that, one day, someone may add a column and break your application as the wrong value will be returned.
This principle is enforced in SQL because you can select named columns, or all columns using the * syntax.
This principle is not enforced in programming languages, where you can usually access the column by ordinal in code, but you should consider the principle before deciding to use a statement such as (psuedo code)
value = results[0].column[2].value;
It should be possible. You'd have to query the system tables (which do vary from one version of SQL to another) to get the 3rd (or Nth) column name as a string to form a following query using that column name.
In SQL 2000 the tables you'll need to start with are syscolumns with a join to sysobjects for the table name. Then the rank() function on "Colid" will give you the Nth column and "name" (shockingly) the name of the column. Once you've got that in a variable the following command can return the value, compare to it, order by it or whatever you need.
This is how you can retrieve a Column's name by passing it's index.
Here variable AcID is used as the index of the column.
Below is the code e.g
dim gFld as string
vSqlText1 = "Select * from RecMast where ID = 1000"
vSql1 = New SqlClient.SqlCommand(vSqlText1, cnnRice)
vRs1 = vSql1.ExecuteReader
if vRs1.Read then
gFld = vRs1.GetName(AcID)
msgbox gfld
end if
declare #searchIndex int
set #searchIndex = 3
select Description from tbl_name t where t.Id = #searchIndex