if I have a column with some values that starts with "%" like this:
[ID]-----[VALUES]
1--------Amount
2--------Percentage
3--------%Amount
4--------%Percentage
how can I have only these two rows with a "select" query?:
[ID]-----[VALUES]
3--------%Amount
4--------%Percentage
I tried these queries but them don't work:
select * from TABLE where VALUES like '[%]%'
select * from TABLE where VALUES like '\%%'
I know that in Java, C and other languages, the backspace \ let you use a jolly character as a normal one like:
var s = "I called him and he sad: \"Hi, there!\"";
There is a similar character/function that do it in SQL?
All answers will be appreciated, thank you for reading the question!
Your query
select * from TABLE where VALUES like '\%%'
should work. The reason it doesn't is because you may have NO_BACKSLASH_ESCAPES enabled which would treat \ as a literal character.
A way to avoid it is using LIKE BINARY
select * from TABLE where VALUES like binary '%'
or with an escape character (can be any character you choose) specification.
select * from TABLE where VALUES like '~%%' escape '~'
try this :
select * from TABLE where VALUES like '%[%]%'
There is an ESCAPE option on LIKE:
select *
from TABLE
where VALUES like '$%%' escape '$';
Anything following the escape character is treated as a regular character. However, the default is backslash (see here), so the version with backslash should do what you want.
Of course, you could also use a regular expression (although that has no hope of using an index).
Note: escape is part of the answer standard so it should work in any database.
You're right that you'll need an escape character for this. In SQL you have to define the escape character.
SELECT * FROM TABLE where VALUES like ESCAPE '!';
I'm pretty sure you can use whatever character you want.
Here's a link to a microsoft explanation that goes into more detail.
Microsoft explanation
MySQL Explanation
Related
Quick questions, I bet the answer is so simple and I am just being blind.
I want to select from the database all the names that only start with "test_1_1_".
I would guess that I do this with;
SELECT * FROM my_table WHERE names LIKE "test_1_1_%";
This doesn't seem to work.
The results keep showing up as
test_1_1_1
test_1_1_2
test_1_11_1
test_1_11_2
test_1_12_1
test_1_12_2
How can I select with MySQL only the results that start with "test_1_1_"?
Thank you in advance.
Wesley
Underscore has a special meaning in LIKE and needs to be escaped:
SELECT * FROM my_table WHERE names LIKE 'test\_1\_1\_%';
You could also use REGEXP here, and avoid the escaping problem:
SELECT * FROM my_table WHERE names REGEXP '^test_1_1_';
When you use _ inside LIKE, it will mean replace that space with any character.
For example, searching for something like field LIKE 'a_' will result in any field with 2 characters starting with "a".
If you really want to search for the underscore characters, you need to escape the value with \ and your query will look like this: LIKE 'test\_1\_1\_%';
The underscore is a single character wildcard when use with LIKE. So to specifically locate an underscore it needs to be "escaped" as follows:
select
*
from mytable
where names like 'test\_1\_1\_%' escape '\'
To test for literal instances of a wildcard character, precede it by
the escape character. If you do not specify the ESCAPE character, \ is
assumed.
https://dev.mysql.com/doc/refman/8.0/en/string-comparison-functions.html
Can do this:
SELECT * FROM my_table WHERE names LIKE "test\_1\_\1\_%";
Consider the following regex
#(.*\..*){2,}
Expected behaviour:
a#b doesnt match
a#b.c doesnt match
a#b.c.d matches
a#b.c.d.e matches
and so on
Testing in regexpal it works as expected.
Using it it in a mysql select doesn't work as expected. Query:
SELECT * FROM `users` where mail regexp '#(.*\..*){2,}'
is returning lines like
foo#example.com
that should not match the given regex. Why?
I think the answer to your question is here.
Because MySQL uses the C escape syntax in strings (for example, “\n”
to represent the newline character), you must double any “\” that you
use in your REGEXP strings.
MYSQL Reference
Because your middle dot wasn't properly escaped it was treated as just another wildcard and in the end your expression was effectively collapsed to #.{2,} or #..+
#anubhava's answer is probably a better substitute for what you tried to do though I would note #dasblinkenlight's comment about using the character class [.] which will make it easy to drop in a regex you've already tested in at RegexPal.
You can use:
SELECT * FROM `users` where mail REGEXP '([^.]*\\.){2}'
to enforce at least 2 dots in mail column.
I would match two dots in MySQL using like:
where col like '%#.%.%'
The problem with your code is that .* (match-everything dot) matches dot '.' character. Replacing it with [^.]* fixes the problem:
SELECT *
FROM `users`
where mail regexp '#([^.]*[.]){2,}'
Note the use of [.] in place of the equivalent \.. This syntax makes it easier to embed the regex into programming languages that use backslash as escape character in their string literals.
Demo.
I've been trying to get a table row with this query:
SELECT * FROM `table` WHERE `field` LIKE "%\u0435\u0442\u043e\u0442%"
Field itself:
Field
--------------------------------------------------------------------
\u0435\u0442\u043e\u0442 \u0442\u0435\u043a\u0441\u0442 \u043d\u0430
Although I can't seem to get it working properly.
I've already tried experimenting with the backslash character:
LIKE "%\\u0435\\u0442\\u043e\\u0442%"
LIKE "%\\\\u0435\\\\u0442\\\\u043e\\\\u0442%"
But none of them seems to work, as well.
I'd appreciate if someone could give a hint as to what I'm doing wrong.
Thanks in advance!
EDIT
Problem solved.
Solution: even after correcting the syntax of the query, it didn't return any results. After making the field BINARY the query started working.
As documented under String Comparison Functions:
Note
Because MySQL uses C escape syntax in strings (for example, “\n” to represent a newline character), you must double any “\” that you use in LIKE strings. For example, to search for “\n”, specify it as “\\n”. To search for “\”, specify it as “\\\\”; this is because the backslashes are stripped once by the parser and again when the pattern match is made, leaving a single backslash to be matched against.
Therefore:
SELECT * FROM `table` WHERE `field` LIKE '%\\\\u0435\\\\u0442\\\\u043e\\\\u0442%'
See it on sqlfiddle.
it can be useful for those who use PHP, and it works for me
$where[] = 'organizer_info LIKE(CONCAT("%", :organizer, "%"))';
$bind['organizer'] = str_replace('"', '', quotemeta(json_encode($orgNameString)));
I am having the following problem:
I have a table T which has a column Name with names. The names have the following structure:
A\\B\C
You can create on yourself like this:
create table T ( Name varchar(10));
insert into T values ('A\\\\B\\C');
select * from T;
Now if I do this:
select Name from T where Name = 'A\\B\C';
That doesn't work, I need to escape the \ (backslash):
select Name from T where Name = 'A\\\\B\\C';
Fine.
But how do I do this automatically to a string Name?
Something like the following won't do it:
select replace('A\\B\C', '\\', '\\\\');
I get: A\\\BC
Any suggestions?
Many thanks in advance.
You have to use "verbatim string".After using that string your Replace function will
look like this
Replace(#"\", #"\\")
I hope it will help for you.
The literal A\\B\C must be coded as A\\\\A\\C, and the parameters of replace() need escaping too:
select 'A\\\\B\\C', replace('A\\\\B\\C', '\\', '\\\\');
output (see this running on SQLFiddle):
A\\B\C A\\\\B\\C
So there is little point in using replace. These two statements are equivalent:
select Name from T where Name = replace('A\\\\B\\C', '\\', '\\\\');
select Name from T where Name = 'A\\\\B\\C';
Usage of regular expression will solve your problem.
This below query will solve the given example.
1) S\\D\B
select * from T where Name REGEXP '[A-Z]\\\\\\\\[A-Z]\\\\[A-Z]$';
if incase the given example might have more then one char
2) D\\B\ACCC
select * from T where Name REGEXP '[A-Z]{1,5}\\\\\\\\[A-Z]{1,5}\\\\[A-Z]{1,5}$';
note: i have used 5 as the max occurrence of char considering the field size is 10 as its mentioned in the create table query.
We can still generalize it.If this still has not met your expectation feel free to ask for my help.
You're confusing what's IN the database with how you represent that data in SQL statements. When a string in the database contains a special character like \, you have to type \\ to represent that character, because \ is a special character in SQL syntax. You have to do this in INSERT statements, but you also have to do it in the parameters to the REPLACE function. There are never actually any double slashes in the data, they're just part of the UI.
Why do you think you need to double the slashes in the SQL expression? If you're typing queries, you should just double the slashes in your command line. If you're generating the query in a programming language, the best solution is to use prepared statements; the API will take care of proper encoding (prepared statements usually use a binary interface, which deals with the raw data). If, for some reason, you need to perform queries by constructing strings, the language should hopefully provide a function to escape the string. For instance, in PHP you would use mysqli_real_escape_string.
But you can't do it by SQL itself -- if you try to feed the non-escaped string to SQL, data is lost and it can't reconstruct it.
You could use LIKE:
SELECT NAME FROM T WHERE NAME LIKE '%\\\\%';
Not exactly sure by what you mean but, this should work.
select replace('A\\B\C', '\', '\\');
It's basically going to replace \ whereever encountered with \\ :)
Is this what you wanted?
I'm working with a MySQL database that has some data imported from Excel. The data contains non-ASCII characters (em dashes, etc.) as well as hidden carriage returns or line feeds. Is there a way to find these records using MySQL?
MySQL provides comprehensive character set management that can help with this kind of problem.
SELECT whatever
FROM tableName
WHERE columnToCheck <> CONVERT(columnToCheck USING ASCII)
The CONVERT(col USING charset) function turns the unconvertable characters into replacement characters. Then, the converted and unconverted text will be unequal.
See this for more discussion. https://dev.mysql.com/doc/refman/8.0/en/charset-repertoire.html
You can use any character set name you wish in place of ASCII. For example, if you want to find out which characters won't render correctly in code page 1257 (Lithuanian, Latvian, Estonian) use CONVERT(columnToCheck USING cp1257)
You can define ASCII as all characters that have a decimal value of 0 - 127 (0x00 - 0x7F) and find columns with non-ASCII characters using the following query
SELECT * FROM TABLE WHERE NOT HEX(COLUMN) REGEXP '^([0-7][0-9A-F])*$';
This was the most comprehensive query I could come up with.
It depends exactly what you're defining as "ASCII", but I would suggest trying a variant of a query like this:
SELECT * FROM tableName WHERE columnToCheck NOT REGEXP '[A-Za-z0-9]';
That query will return all rows where columnToCheck contains any non-alphanumeric characters. If you have other characters that are acceptable, add them to the character class in the regular expression. For example, if periods, commas, and hyphens are OK, change the query to:
SELECT * FROM tableName WHERE columnToCheck NOT REGEXP '[A-Za-z0-9.,-]';
The most relevant page of the MySQL documentation is probably 12.5.2 Regular Expressions.
This is probably what you're looking for:
select * from TABLE where COLUMN regexp '[^ -~]';
It should return all rows where COLUMN contains non-ASCII characters (or non-printable ASCII characters such as newline).
One missing character from everyone's examples above is the termination character (\0). This is invisible to the MySQL console output and is not discoverable by any of the queries heretofore mentioned. The query to find it is simply:
select * from TABLE where COLUMN like '%\0%';
Based on the correct answer, but taking into account ASCII control characters as well, the solution that worked for me is this:
SELECT * FROM `table` WHERE NOT `field` REGEXP "[\\x00-\\xFF]|^$";
It does the same thing: searches for violations of the ASCII range in a column, but lets you search for control characters too, since it uses hexadecimal notation for code points. Since there is no comparison or conversion (unlike #Ollie's answer), this should be significantly faster, too. (Especially if MySQL does early-termination on the regex query, which it definitely should.)
It also avoids returning fields that are zero-length. If you want a slightly-longer version that might perform better, you can use this instead:
SELECT * FROM `table` WHERE `field` <> "" AND NOT `field` REGEXP "[\\x00-\\xFF]";
It does a separate check for length to avoid zero-length results, without considering them for a regex pass. Depending on the number of zero-length entries you have, this could be significantly faster.
Note that if your default character set is something bizarre where 0x00-0xFF don't map to the same values as ASCII (is there such a character set in existence anywhere?), this would return a false positive. Otherwise, enjoy!
Try Using this query for searching special character records
SELECT *
FROM tableName
WHERE fieldName REGEXP '[^a-zA-Z0-9#:. \'\-`,\&]'
#zende's answer was the only one that covered columns with a mix of ascii and non ascii characters, but it also had that problematic hex thing. I used this:
SELECT * FROM `table` WHERE NOT `column` REGEXP '^[ -~]+$' AND `column` !=''
In Oracle we can use below.
SELECT * FROM TABLE_A WHERE ASCIISTR(COLUMN_A) <> COLUMN_A;
for this question we can also use this method :
Question from sql zoo:
Find all details of the prize won by PETER GRÜNBERG
Non-ASCII characters
ans: select*from nobel where winner like'P% GR%_%berg';