I want to find which SP a column named column1 is modified by UPDATE query by searching sys.sql_module, and since the column is also used in SELECT queries, I think its better to use '%Column1 =%' criteria as LIKE predicate.
However, system coding standard is not strictly applied, therefore in our database there exists multiple type of codings: column1=, column1 =,column1 {tab} =, column1 +=, column1 {CR}{LF} = and etc. Definitely i can't use %column1%=% as predicate, but how can I find all (at least most) of them meet my initial predicate?
Assume I accept maximum 10 chars between column1 and = is accepted.
I was in the same situation in the past. What my work around was, I removed every space, new line and tab from sql_modules definition column itself then compared with my searched string.
Select SP_Def from
(SELECT REPLACE(REPLACE(REPLACE(sm.definition, ' ',''), CHAR(13) +CHAR(10),''),CHAR(9),'') as SP_Def
FROM sys.sql_modules AS sm ) a
where SP_Def like '%column1=%'
Related
I came up with a query, to fetch data from a table, which contains 93781665 entries, to display the results as suggestions in an autocomplete text box.
But it takes more than 300 Sec to fetch results.
The query is given below.
select * from table
where upper(column1||' '||column2||' '||column3) like upper('searchstring%')
and rownum <= 10;
Kindly help me to optimize it.
The WHERE clause in your query is not sargable, meaning that no index can be used there. This rules out most of the methods you might use here to optimize the query. Here is one suggestion:
SELECT *
FROM yourTable
WHERE column4 LIKE 'SEARCHSTRING%';
Here, column4 is a new column in your table, which contains the concatenation of the first three columns. Furthermore, all text in column4 will always be uppercase, and the search string you pass into the query will also always be uppercase. Given these assumptions, the following index might help the query:
CREATE INDEX idx ON yourTable (column4);
In Oracle, you can index an expression:
create index idx_t_columns on t(upper(column1||' '||column2||' '||column3))
Then, this condition can use the index:
where upper(column1||' '||column2||' '||column3) like 'searchstring%'
If the search string is constant, then this should also work:
where upper(column1||' '||column2||' '||column3) like upper('searchstring%')
Note that a wildcard at the beginning of the like pattern would preclude the use of an index.
I have a table with column mapping which store record: "IV=>0J,IV=>0Q,IV=>2,V=>0H,V=>0K,VI=>0R,VI=>1,"
What is the sql to check whether or not a substring is in column mapping.
so, I would like this:
if I have "IV=>0J" would return true, because IV=>0J is exact in string "mapping"
if I have "IV=>01" would return false. And so on...
I try this:
SELECT * FROM table WHERE charindex('IV=>0J',mapping)
But when I have "IV=>0", it returns TRUE. But, it should return FALSE.
Thank You..
You can search with commas included. Just also add one at beginning and end of mapping:
SELECT * FROM table WHERE charindex(',IV=>0J,',',' + mapping + ',') <> 0
or
SELECT * FROM table WHERE ',' + mapping + ',' LIKE '%,IV=>OJ,%'
This should do the trick:
SELECT * FROM table
WHERE
mapping LIKE '%,IV=>0J,%'
OR mapping LIKE '%,IV=>0J'
OR mapping LIKE 'IV=>0J,%'
OR mapping = 'IV=>0J'
But you should really normalize the database - you are currently violating the principle of atomicity, and therefore the 1NF. Your current difficulties in querying and the future difficulties with performance that you are about to encounter all stem from this root problem...
While you can search by including a comma in the string, this is a bad design for several reasons.
You are unable to take advantage of indexing
You force a full scan of the table, which will lead to bad performance AND excessive blocking.
You have to make sure that there is always a leading or a trailing comma (depends on what you expect in your LIKE expression).
You are no longer able to edit a single entry, you'll have to replace the entire string each time you want to change even a single mapping.
You open yourself to a concurrency nightmare if more that one users try to update different mappings that just happen to be stored in the same column.
Your table isn't even in 1st normal form any more, which is why you have such difficulties
You should normalize your mapping column, by extracting the data to a different mapping table, with at least the From and To columns you require. You can then add these columns to an index an convert your query using only a single index seek.
You can also add the ID values of your source table to the Mappings table and the index. This will allow you to convert the lookup for a source row to a join between the two tables that takes advantage of indexing
charindex returns the position of the text, not Boolean.
to check if the text exists, compare to 0:
SELECT * FROM table WHERE charindex('IV=>0J',mapping) <> 0
I think you're missing something here, the Charindex function does not return TRUE or FALSE.
It returns the starting point of the substring inside master string, or if the substring is not present, then -1.
So you query should read,
SELECT * FROM table WHERE charindex('IV=>0J',mapping) > 0
I need to match on a partial string but can't turn full-text indexing on so can't use contains. I've looked at Levenstein's function for determining the distance between two strings but I'm not looking for fuzzy matching but that every character in the column exists in the string.
I.e. If the string being passed is something like AB_SYS_20120430.TXT I want to match on any columns containing AB_SYS. The like predicate isn't getting me there. I really need the equivalent of the .NET contains feature but as mentioned turning on full text indexing isn't an option to be turned on. Thought I would see if there were any other possible work arounds.
Are you looking for the LIKE function?
http://www.w3schools.com/sql/sql_like.asp
... WHERE MyColumn LIKE '%AB_SYS%'
That may not be optimal, but it seems like it answers your question... If you can search from only the left or right side that could further optimize.
That is functionally similar to String.Contains
http://msdn.microsoft.com/en-us/library/dy85x1sa.aspx
EDIT: How will you parse the input text into the "relevant" substring?
EDIT: To search the same LIKE condition but reverse, from your partial column to the complete literal, simply append the wildcard characters:
... WHERE 'AB_SYS_20120430.TXT' LIKE '%' + MyColumn + '%'
EDIT: You have suggested that you can't get it to work. If you add the schema do your question then I can help you further but consider this:
You have a table called MyTable
In that table there is a column called MyColumn
Some rows in that table have the data 'AB_SYS' in MyColumn
Given the parameter 'AB_SYS_20120430.TXT' you want to return all matching rows
CREATE PROCEDURE MyTestProcedure
#pFullNameString nvarchar(4000) = '' -- parameter passed in, like AB_SYS_20120430.TXT
AS
BEGIN
SELECT
*
FROM
MyTable
WHERE
#pFullNameString LIKE '%' + MyTable.[MyColumn] + '%'
END
GO
You could use CHARINDEX
WHERE CHARINDEX(StringToCheckFor, StringToCheckIn) > 0
I have a table A with this column:
IDS(VARCHAR)
1|56|23
I need to run this query:
select TEST from TEXTS where ID in ( select IDS from A where A.ID = xxx )
TEXTS.ID is an INTEGER. How can I split the string A.IDS into several ints for the join?
Must work on MySQL and Oracle. SQL99 preferred.
First of all, you should not store data like this in a column. You should split that out into a separate table, then you would have a normal join, and not this problem.
Having said that, what you have to do is the following:
Convert the number to a string
Pad it with the | (your separator) character, before it, and after it (I'll tell you why below)
Pad the text you're looking in with the same separator, before and after
Do a LIKE on it
This will run slow!
Here's the SQL that does what you want (assuming all the operators and functions work in your SQL dialect, you don't say what kind of database engine this is):
SELECT
TEXT -- assuming this was misspelt?
FROM
TEXTS -- and this as well?
JOIN A ON
'|' + A.IDS + '|' LIKE '%|' + CONVERT(TEXTS.ID) + '|%'
The reason why you need to pad the two with the separator before and after is this: what if you're looking for the number 5? You need to ensure it wouldn't accidentally fit the 56 number, just because it contained the digit.
Basically, we will do this:
... '|1|56|23|' LIKE '%|56|%'
If there is ever only going to be 1 row in A, it might run faster if you do this (but I am not sure, you would need to measure it):
SELECT
TEXT -- assuming this was misspelt?
FROM
TEXTS -- and this as well?
WHERE
(SELECT '|' + IDS + '|' FROM A) LIKE '%|' + CONVERT(TEXTS.ID) + '|%'
If there are many rows in your TEXTS table, it will be worth the effort to add code to generate the appropriate SQL by first retrieving the values from the A table, construct an appropriate SQL with IN and use that instead:
SELECT
TEXT -- assuming this was misspelt?
FROM
TEXTS -- and this as well?
WHERE
ID IN (1, 56, 23)
This will run much faster since now it can use an index on this query.
If you had A.ID as a column, and the values as separate rows, here's how you would do the query:
SELECT
TEXT -- assuming this was misspelt?
FROM
TEXTS -- and this as well?
INNER JOIN A ON TEXTS.ID = A.ID
This will run slightly slower than the previous one, but in the previous one you have overhead in having to first retrieve A.IDS, build the query, and risk producing a new execution plan that has to be compiled.
Oracle 10g DB. I have a table called s_contact. This table has a field called person_uid. This person_uid field is a varchar2 but contains valid numbers for some rows and in-valid numbers for other rows. For instance, one row might have a person_uid of '2-lkjsdf' and another might be 1234567890.
I want to return just the rows with valid numbers in person_uid. The SQL I am trying is...
select person_uid
from s_contact
where decode(trim(translate(person_uid, '1234567890', ' ')), null, 'n', 'c') = 'n'
The translate replaces all numbers with spaces so that a trim will result in null if the field only contained numbers. Then I use a decode statement to set a little code to filter on. n=number, c=char.
This seems to work when I run just a preview, but I get an 'invalid number' error when I add a filter of...
and person_uid = 100
-- or
and to_number(person_uid) = 100
I just don't understand what is happening! It should be filtering out all the records that are invalid numbers and 100 is obviously a number...
Any ideas anyone? Greatly Appreciated!
Unfortunately, the various subquery approaches that have been proposed are not guaranteed to work. Oracle is allowed to push the predicate into the subquery and then evaluate the conditions in whatever order it deems appropriate. If it happens to evaluate the PERSON_UID condition before filtering out the non-numeric rows, you'll get an error. Jonathan Gennick has an excellent article Subquery Madness that discusses this issue in quite a bit of detail.
That leaves you with a few options
1) Rework the data model. It's generally not a good idea to store numbers in anything other than a NUMBER column. In addition to causing this sort of issue, it has a tendency to screw up the optimizer's cardinality estimates which leads to less than ideal query plans.
2) Change the condition to specify a string value rather than a number. If PERSON_UID is supposed to be a string, your filter condition could be PERSON_UID = '100'. That avoids the need to perform the implicit conversion.
3) Write a custom function that does the string to number conversion and ignores any errors and use that in your code, i.e.
CREATE OR REPLACE FUNCTION my_to_number( p_arg IN VARCHAR2 )
RETURN NUMBER
IS
BEGIN
RETURN to_number( p_arg );
EXCEPTION
WHEN others THEN
RETURN NULL;
END;
and then my_to_number(PERSION_UID) = 100
4) Use a subquery that prevents the predicate from being pushed. This can be done in a few different ways. I personally prefer throwing a ROWNUM into the subquery, i.e. building on OMG Ponies' solution
WITH valid_persons AS (
SELECT TO_NUMBER(c.person_uid) 'person_uid',
ROWNUM rn
FROM S_CONTACT c
WHERE REGEXP_LIKE(c.personuid, '[[:digit:]]'))
SELECT *
FROM valid_persons vp
WHERE vp.person_uid = 100
Oracle can't push the vp.person_uid = 100 predicate into the subquery here because doing so would change the results. You could also use hints to force the subquery to be materialized or to prevent predicate pushing.
Another alternative is to combine the predicates:
where case when translate(person_uid, '1234567890', ' ')) is null
then to_number(person_uid) end = 100
When you add those numbers to the WHERE clause it's still doing those checks. You can't guarantee the ordering within the WHERE clause. So, it still tries to compare 100 to '2-lkjsdf'.
Can you use '100'?
Another option is to apply a subselect
SELECT * FROM (
select person_uid
from s_contact
where decode(trim(translate(person_uid, '1234567890', ' ')), null, 'n', 'c') = 'n'
)
WHERE TO_NUMBER(PERSON_UID) = 100
Regular expressions to the rescue!
where regexp_like (person_uid, '^[0-9]+$')
Use the first part of your query to generate a temp table. Then query the temp table based on person_uid = 100 or whatever.
The problem is that oracle tries to convert each person_uid to an int as it gets to it due to the additional and statement in your where clause. This behavior may or may not show up in the preview depending on what records where picked.