My user table has a column "name" which contains information like this:
Joe Lee
Angela White
I want to search for either first name or last name efficiently. First name is easy, I can do
SELECT * FROM user WHERE name LIKE "ABC%"
But for last name, if I do
SELECT * FROM user WHERE name LIKE "%ABC"
That would be extremely slow.
So I am thinking about counting the characters of the input, for example, "ABC" has 3 characters, and if I can search only the last three characters in name column, that would be great. So I want something like
SELECT * FROM user WHERE substring(name, end-3, end) LIKE "ABC%"
Is there anything in MySQL that can do this?
Thanks so much!
PS. I cannot do fulltext because our search engine doesn't support that.
The reason that
WHERE name LIKE '%ith'
is a slow way to look for 'John Smith' by last name is the same reason that
WHERE Right(name, InStr(name, ' ' )) LIKE 'smi%'
or any other expression on the column is slow. It defeats the use of the index for quick lookup and leaves the MySQL server doing a full table scan or full index scan.
If you were using Oracle (that is, if you worked for a formerly wealthy employer) you could use function indexes. As it is you have to add some extra columns or some other helping data to accelerate your search.
Your smartest move is to split your first and last names into separate columns. Several other people have pointed out good reasons for doing that.
If you can't do that you could try creating an extra column which contains the name string reversed, and create an index on that column. That column will have, for example, 'John Smith' stored as 'htimS nhoJ'. Then you can search as follows.
WHERE nameReversed LIKE CONCAT(REVERSE('ith'),'%')
This search will use the index and be decently fast. I've had good success with it.
You're close. In MySQL you should be able to use InStr(str, substr) and Right(str, index) to do the following:
SELECT * FROM user WHERE Right(name, InStr(name, " ")) LIKE "ABC%"
InStr(name, " ") returns the index of the Space character (you may have to play with the " " syntax). This index is then used in the Right() function to search for only the last name (basically; problems arise when you have multiple names, multiple spaces etc). LIKE "ABC%" would then search for a last name starting with ABC.
You cannot use a fixed index as names that are more than 3 or less than 3 characters long would not return properly as you suggest.
However, as Zane said, it's a much better practise to use seperate fields.
If it is a MyIsam table, you may use Free text search to do the same.
You can use the REGEXP operator:
SELECT * FROM user WHERE name REGEXP "ABC$"
http://dev.mysql.com/doc/refman/5.1/en/regexp.html
I am struggling with this query and want to know if I am wasting my time and need to write a php script or is something like the following actually possible?
UPDATE my_table
SET #userid = user_id
AND SET filename('http://pathto/newfilename_'#userid'.jpg')
FROM my_table
WHERE filename
LIKE '%_%' AND filename
LIKE '%jpg'AND filename
NOT LIKE 'http%';
Basically I have 700 odd files that need renaming in the database as they do not match the filenames as I am changing system, they are called in the database.
The format is 2_gfhgfhf.jpg which translates to userid_randomjumble.jpg
But not all files in the database are in this format only about 700 out of thousands. So I want to identify names that contain _ but don't contain http (thats the correct format that I don't want to touch).
I can do that fine but now comes the tricky bit!!
I want to replace that file name userid_randomjumble.jpg with http://pathto/filename_userid.jpg So I want to set the column user_id in that row to a variable and insert it into my new filename.
The above doesn't work for obvious reasons but I am not sure if there is a way round what I'm trying to do. I have no idea if it's possible? Am I wasting my time with this and should I turn to PHP with mysql and stop being lazy? Or is there a way to get this to work?
Yes it is possible without the php. Here is a simple example
SET #a:=0;
SELECT * FROM table WHERE field_name = #a;
Yes you can do it using straightforward SQL:
UPDATE my_table
SET filename = CONCAT('http://pathto/newfilename_', userid, '.jpg')
WHERE filename LIKE '%\_%jpg'
AND filename NOT LIKE 'http%';
Notes:
No need for variables. Any columns of rows being updated may be referenced
In mysql, use CONCAT() to add text values together
With LIKE, an underscore (_) has a special meaning - it means "any single character". If you want to match a literal underscore, you must escape it with a backslash (\)
Your two LIKE predicates may be safely merged into one for a simpler query
pls give me the SQL to copy and paste in order to make an nested if statement that meets the following 3 conditons. Thank you very much in advance:
where if the field “Activity Number” doesn’t contain the character "/” e.g ”1-100ZUOM1”, then add a suffix ”/1” e.g. ”1-100ZUOM1/1”
if it already does contain a suffix like ”/1” e.g. ”1-100ZUOM1/1”, then change the last character to “2” e.g. ”1-100ZUOM1/2”
if it already does contain a suffix like ”/2” e.g. ”1-100ZUOM1/2”, then change the last character to “3” e.g. ”1-100ZUOM1/3”
INSERT INTO tbl_All_workorders ( [Activity Number] )
SELECT AW.[Activity Number]
FROM tbl_All_workorders AS AW;
Consider altering your design so that Activity Number is stored split into two columns so that the suffix appears in its own integer column. This way, your SQL updates will be far easier to maintain and the Activity Number can be easily concatenated for display, possibly using a VIEW.
I am new to SQL and I have several large database with upper case first and last names that I need to convert to proper case in SQL sever 2008.
I am using the following to do this:
update database
Set FirstNames = upper(substring(FirstNames, 1, 1))
+ lower(substring(FirstNames, 2, (len(FirstNames) - 1) ))
I was wondering if there was any way to adapt this so that a field with two first names is also updated (currently I make the change and then go through and manually change the second name).
I have looked over the other answers in this field and they all seem quit long, compared to the query above.
Also is there any way to assist with converting the Mc suranmes ( I will manually change the others)? MCDONALD to McDonald, again I am just using the about query but replacing the FirstNames with LastName.
This is probably best done outside of SQL. However, if there is a requirement to do it on the server or if speed isn't an issue (because it will be an issue so you need to figure out if you care), the way you are going about it is probably the best way of doing so. If you want, you could create a UDF that puts all of the logic in one area.
Here is some code I came across (with attribution and more information below it):
CREATE FUNCTION dbo.fCapFirst(#input NVARCHAR(4000)) RETURNS NVARCHAR(4000)
AS
BEGIN
DECLARE #position INT
WHILE IsNull(#position,Len(#input)) > 1
SELECT #input = Stuff(#input,IsNull(#position,1),1,upper(substring(#input,IsNull(#position,1),1))),
#position = charindex(' ',#input,IsNull(#position,1)) + 1
RETURN (#input)
END
--Call it like so
select dbo.fCapFirst(Lower(Column)) From MyTable
I got this code from http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=37760 There is more information and other suggestions in this forum as well.
As for dealing with cases like the McDonald, I would suggest one of two ways to handle this. One would be to put a search in the above UDF for key names ('McDonald', 'McGrew', etc.) or for patterns (the first two letters are Mc then make the next one capital, etc.) The second way would be to put these cases (the full names) in a table and have their replacement value in a second column. Then simply do a replace. Most likely, however, it will be easiest to identify rules like Mc then capitalize instead of trying to list every last-name possibility.
Don't forget you may want to modify the above UDF to include dashes, not just spaces.
Maybe this is too long but it is very easy and can be adapted for -, ', etc:
UPDATE tbl SET LastName = Case when (CharIndex(' ',lastname,1)<>0) then (Upper(Substring(lastname,1,1))+Lower(Substring(lastname,2,CharIndex(' ',lastname,1)-1)))+
(Upper(Substring(lastname,CharIndex(' ',lastname,1)+1,1))+
Lower(Substring(lastname,CharIndex(' ',lastname,1)+2,Len(lastname)-(CharIndex(' ',lastname,1)-1))))
else (Upper(Substring(lastname,1,1))+Lower(Substring(lastname,2,Len(lastname)-1))) end,
FirstName = Case when (CharIndex(' ',firstname,1)<>0) then (Upper(Substring(firstname,1,1))+Lower(Substring(firstname,2,CharIndex(' ',firstname,1)-1)))+
(Upper(Substring(firstname,CharIndex(' ',firstname,1)+1,1))+
Lower(Substring(firstname,CharIndex(' ',firstname,1)+2,Len(firstname)-(CharIndex(' ',firstname,1)-1))))
else (Upper(Substring(firstname,1,1))+Lower(Substring(firstname,2,Len(firstname)-1))) end;
Tony Rogerson has code that deals with:
double barrelled names eg Arthur Bentley-Smythe
Control characters
I haven't used it myself though...
I have an InnoDB database table of 12 character codes which often need to be entered by a user.
Occasionally, a user will enter the code incorrectly (for example typing a lower case L instead of a 1 etc).
I'm trying to write a query that will find similar codes to the one they have entered but using LIKE '%code%' gives me way too many results, many of which contain only one matching character.
Is there a way to perform a more detailed check?
Edit - Case sensitive not required.
Any advice appreciated.
Thanks.
Have a look at soundex. Commonly misspelled strings have the same soundex code, so you can query for:
where soundex(Code) like soundex(UserInput)
use without wildcard % for that
SELECT `code` FROM table where code LIKE 'user_input'
thi wil also check the space
SELECT 'a' = 'a ', return 1 whereas SELCET 'a' LIKE 'a ' return 0
reference