I have a string like this format. In my case I need to extract only the characters from string case
1)12AB
2)SD12
3)1WE4
output
1)AB
2)SD
3)WE
I need to extract only the characters. I am using this expression in the derived column in SSIS package
SUBSTRING(MediaIDCode,1,2)
but this expression works for only this condition
1)12AB
I need to get an expression that works for all the conditions above. I have tried using REPLACE ( '' , '1', '') but it becomes a big expression.
The SUBSTRING function code you've posted will extract characters from a string without considering their content.
Have a look at using Regular Expressions to filter out unwanted characters:
http://consultingblogs.emc.com/jamiethomson/archive/2005/07/04/SSIS-Nugget_3A00_-The-script-component-and-regular-expressions.aspx
You could also use a synchronous script transformation to filter characters this way:
Dim NewMediaIDCode As String = ""
For Each c As Char In Row.MediaIDCode
If Not Char.IsDigit(c) Then
NewMediaIDCode += c
End If
Next
Row.MediaIDCode = NewMediaIDCode
I've used the IsDigit method here, but there's plenty of other methods to choose from.
Related
I have one column(varchar) containing only json string within one table. I want replace all keys with "" on that column. How can I do that using sql? My database is MySQL.
For example:
|--------------------------------------------------------------------|
| t_column |
|--------------------------------------------------------------------|
| {"name":"mike","email":"xxx#example.com","isManage":false,"age":22}|
|--------------------------------------------------------------------|
SELECT replace(t_column, regexp, "") FROM t_table
I expect:
mikexxx#example.comfalse22
How to write that regexp?
Start from
select t_column->'$.*' from test
This will return a JSON array of attribute values:
[22, "mike", "xxx#example.com", false]
This might be already all you need, and you can try something like
select *
from test
where t_column->'$.*' like '%mike%';
Unfortunately there seems to be no native way to join array values to a single string like JSON_ARRAY_CONCAT(). In MySQL 8.0 you can try REGEXP_REPLACE() and strip all JSON characters:
select regexp_replace(t_column->'$.*', '[" ,\\[\\]]', '') from test
which will return '22mikexxx#example.comfalse'.
If the values can contain one of those characters, they will also be removed.
Note: That isn't very reliable. But it's all I can do in a "simple" way.
See demo on db-fiddle.
I could be making it too simplistic, but this is just a mockup based on your comment. I can formalize it into a query if it fits your requirement.
Let's say you get your JSON string to this format where you replace all the double quotes and curly brackets and then add a comma at the end. After playing with replace and concat_ws, you are now left with:
name:mike,email:xxx#example.com,isManage:false,age:22,
With this format, every value is now preceded by a semicolon and followed by a comma, which is not true for the key. Let's say you now want to see if this JSON string has the value "mike" in it. This, you could achieve using
select * from your_table where json_col like '%:mike,%';
If you really want to solve the problem with your approach then the question becomes
What is the regex that selects all the undesired text from the string {"name":"mike","email":"xxx#example.com","isManage":false,"age":22} ?
Then the answer would be: {\"name\":\"|\"email\":\"|\",\"isManage\":|,\"age\":|}
But as others let you notice I would actually approach the problem parsing JSONs. Look up for functions json_value and json_query
Hope I helped
PS: Keep close attention on how I structured the bolded sentence. Any difference changes the problem.
EDIT:
If you want a more generic expression, something like select all the text that is not a value on a json-formatted string, you can use this one:
{|",|"\w+\":|"|,|}
I need a function in R that mimics the functionality of LIKE in MySQL.
(I need to validate outcomes of SQL queries and R scripts against each other. If I had a function that exists to mimic the functionality of LIKE, great, that reduces my workload.)
I am adding some of the behaviors of LIKE from the link above. As you can see, there are ways in which LIKE differs from the standard grep regex.
LIKE (description from the link)
Pattern matching using SQL simple regular expression comparison. Returns 1 (TRUE) or 0 (FALSE).
Per the SQL standard, LIKE performs matching on a per-character basis, thus it can produce results different from the = comparison operator:
Trailing spaces are significant
With LIKE you can use the following two wildcard characters in the pattern.
Character Description
% Matches any number of characters, even zero characters
_ Matches exactly one character
In MySQL, LIKE is permitted on numeric expressions. (This is an extension to the standard SQL LIKE.)
mysql> SELECT 10 LIKE '1%';
-> 1
Try sqldf package. You can write sql-like queries on data.frame
For example:
require(sqldf)
data(CO2)
new.data <- sqldf("select * from CO2 where Plant like 'Qn%'")
try ?grepl or package sqldf
df=data.frame(A=c("mytext_is_here","anothertext_is_here","mytext_is_also_here"),B=1:3)
df
firstSolution = subset(df, grepl("^mytext", A))
library("sqldf")
secondSolution = sqldf("select * from df where A like 'mytext%'")
Source: page 8 of http://cran.r-project.org/web/packages/sqldf/sqldf.pdf
I think you could use grepl function in R to do the same.
grepl does partial string matching and it will return a logical vector which you could later use to subset data along with other conditions as well.
You could also later use '!' sign in front of grepl to filter out the results having that expression.
ex. sample=c("data","ddata","ddata1")
filtered_data=grepl("dd",sample)
# it gives a logical vector FALSE TRUE TRUE
#and it can be used as follows to find out all the elements that have a string "dd" in it.
sample[grepl("dd",sample)]
Please note that grepl is case sensitive.
I have two databases, both containing phone numbers. I need to find all instances of duplicate phone numbers, but the formats of database 1 vary wildly from the format of database 2.
I'd like to strip out all non-digit characters and just compare the two 10-digit strings to determine if it's a duplicate, something like:
SELECT b.phone as barPhone, sp.phone as SPPhone FROM bars b JOIN single_platform_bars sp ON sp.phone.REGEX = b.phone.REGEX
Is such a thing even possible in a mysql query? If so, how do I go about accomplishing this?
EDIT: Looks like it is, in fact, a thing you can do! Hooray! The following query returned exactly what I needed:
SELECT b.phone, b.id, sp.phone, sp.id
FROM bars b JOIN single_platform_bars sp ON REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(b.phone,' ',''),'-',''),'(',''),')',''),'.','') = REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(sp.phone,' ',''),'-',''),'(',''),')',''),'.','')
MySQL doesn't support returning the "match" of a regular expression. The MySQL REGEXP function returns a 1 or 0, depending on whether an expression matched a regular expression test or not.
You can use the REPLACE function to replace a specific character, and you can nest those. But it would be unwieldy for all "non-digit" characters. If you want to remove spaces, dashes, open and close parens e.g.
REPLACE(REPLACE(REPLACE(REPLACE(sp.phone,' ',''),'-',''),'(',''),')','')
One approach is to create user defined function to return just the digits from a string. But if you don't want to create a user defined function...
This can be done in native MySQL. This approach is a bit unwieldy, but it is workable for strings of "reasonable" length.
SELECT CONCAT(IF(SUBSTR(sp.phone,1,1) REGEXP '^[0-9]$',SUBSTR(sp.phone,1,1),'')
,IF(SUBSTR(sp.phone,2,1) REGEXP '^[0-9]$',SUBSTR(sp.phone,2,1),'')
,IF(SUBSTR(sp.phone,3,1) REGEXP '^[0-9]$',SUBSTR(sp.phone,3,1),'')
,IF(SUBSTR(sp.phone,4,1) REGEXP '^[0-9]$',SUBSTR(sp.phone,4,1),'')
,IF(SUBSTR(sp.phone,5,1) REGEXP '^[0-9]$',SUBSTR(sp.phone,5,1),'')
) AS phone_digits
FROM sp
To unpack that a bit... we extract a single character from the first position in the string, check if it's a digit, if it is a digit, we return the character, otherwise we return an empty string. We repeat this for the second, third, etc. characters in the string. We concatenate all of the returned characters and empty strings back into a single string.
Obviously, the expression above is checking only the first five characters of the string, you would need to extend this, basically adding a line for each position you want to check...
And unwieldy expressions like this can be included in a predicate (in a WHERE clause). (I've just shown it in the SELECT list for convenience.)
MySQL doesn't support such string operations natively. You will either need to use a UDF like this, or else create a stored function that iterates over a string parameter concatenating to its return value every digit that it encounters.
I am using MySQL with MATLAB, and I want to get a name from user, and pass it to the table in mySQL, but it is rejecting a variable name in place of string
var_name=input('enter the name:');
mysql('insert into table (name) values (var_name)');
Any suggestions?
FIRST read the comments to this question - you don't want to shoot yourself in the foot with a mysql injection security problem. You have been warned. Now, to solve your current problem, without addressing the security risk of the whole approach when it comes to building SQL queries, read on...
In principle Amro has already posted two solutions for you which work, but since you have not accepted it I'll explain further.
Your problem is that you are not telling MATLAB which parts of your query it should interpret as a literal string, and which parts it should interpret as a variable name. To solve this, you can just end the literal string where appropriate, i.e. after the opening brackets, and then start them again before the closing brackets.
In between those literal strings you want to add the contents of your variables, so you need to tell MATLAB to concat your literal strings with your variables, since the mysql command probably expects the whole query as a single string. So in essence you want to take the string 'insert into table(' and the string saved in the variable name and the string ') values (' and so on and glue them into one big string. Amro and Isaac have shown you two solutions of how to do this without much explanation:
horzcat('insert into table (', name, ') values (', var_name, ')')
uses the function horzcat, while
['insert into table (' name ') values (' var_name ')']
uses the fact that MATLAB treats strings as arrays of characters so that you can just use square brackets to form a large array containing the strings one after the other.
The third solution, offered by Amro, is a bit more sublte:
sprintf('insert into table (%s) values (%s)',name,var_name)
It tells the function sprintf (which is made for that purpose) "take the string which I supply as first parameter and replace occurences of %s with the strings I supply as the following parameters. This last technique is in particular useful if you also need to insert numbers into your string, because sprintf can also convert numbers to string and allows fine control over how they are formatted. You should have a close look at the help page for sprintf to know more :-).
Try this instead:
mysql(['insert into table (' name ') values (' var_name ')']);
or even:
mysql(sprintf('insert into table (%s) values (%s)',name,var_name));
I believe the problem you are having is the same as the one in this other question. It sounds like you want to create a command string that itself contains a ' delimited string, which would require you to escape each ' with another ' when you create your command string (note the first example in this string handling documentation). Note also you may want to use the 's' option for the INPUT function:
var_name = input('Enter the name: ','s'); %# Treats input like a string
commandString = sprintf('insert into table (name) values (''%s'')', var_name);
%# Note the two apostrophes --^
mysql(commandString);
If I were to enter Ken for the input, the string commandString would contain the following:
insert into table (name) values ('Ken')
And of course, as others have already mentioned, beware injection vulnerabilities.
I need a PHP regular expression that will compare stings similar to mysql Match Against behaviour.
e.g:
string = "findmatches";
$pattern = 'fildcatches';
this pattern is supposed to match the string
Thanks a lot
Regular expression may not be the best solution for your needs, try instead the PHP construct similar_text() :
http://php.net/manual/en/function.similar-text.php
The function returns the similarity between two strings in percentage and the number of matching chars.