I have two databases on MariaDB with InnoDB as engine, with both DB having latin_swedish_ci as collation, but one has latin_swedish_ci as table collation and other utf8_general_ci as table collation, when I execute left excluding join on database with the following query:
SELECT `ct`.`name`
FROM `csv_temp` as `ct`
left join `trans_recs` as `tr` on `ct`.`name` = `tr`.`name`
where `tr`.`name` is null and `ct`.`fk_project_id` = 1
I get correct results on DB and table both with latin_swedish_ci collation but empty set on DB with latin_swedish_ci and table with utf8_general_ci.
Is there an explanation for his behaviour. Thanks in advance.
Does ISNULL on MySql work differently with collation latin_swedish_ci and utf8_general_ci
It does not. ISNULL will work when the cell is null regarding of the collation.
I get correct results on DB and table both with latin_swedish_ci collation but empty set on DB with latin_swedish_ci and table with utf8_general_ci.
Maybe the default is an empty string and not NULL with the collation latin_swedish_ci
This question already has answers here:
What does character set and collation mean exactly?
(4 answers)
Closed 8 years ago.
1/ Sometime you write
ALTER DATABASE [MyDb] COLLATE SQL_Latin1_General_CP1_CI_AS
after a moment, if you try
ALTER DATABASE [MyDb] COLLATE FRENCH_CI_AS
it may not succeed. why this?
2/ if table1 is SQL_Latin1_General_CP1_CI_AS and if table2 is FRENCH_CI_AS
one cannot write ...where table1.field1= table2.field2
What is the consequence of COLLATE in a database or table ?
you can compare your query with collate name
table1.field1 = table2.field2 COLLATE FRENCH_CI_AS
otherwise Alter Column.(If you want to change field COLLATE)
ALTER TABLE [dbo].[TableName]
ALTER COLUMN [FieldName] [DataType] COLLATE [Collate Name] NOT NULL
This answer is based on experience from working with Ms Sql Server. I have only a little experience from working with other databases, but I imagine much of this would apply for them as well.
From Msdn (here):
Collations let users sort and compare strings according to their own
conventions
Collations are used to let sql server know which characters are considered the same. If a case insensitive collation is used, X and x are considered the same. If a case sensitive collation is used, they are different. In an accent insensitive collation e and é might be considered the same, while in an accent sensitive collation they are different.
At least with Ms Sql Server, if you are comparing two strings that are stored in different collations, you must tell the server which collation to use in the comparison by using the COLLATE clause already mentioned in other answers. Not sure about how this is done in other databases.
If your table contains a row with a column that contains the text ÖBc and you select from this table like so:
select COL from TBL where COL = 'obc'
Then the row will be found using a case and accent insensitive collation like latin1_general_ci_ai. Accent insensitivity means that O and Ö are the same, and case insensitivity takes care of the case mismatch.
With the same select and collation latin1_general_cs_ai the row will not be found because of case sensitivity.
Similarly with collation latin1_general_ci_as, the row will not be found because of accent sensitivity.
Collation is also used to determine alphabetical sort order when sorting results. This determines if upper and lower case charachers are sorted differently and also where accented charaters are sorted.
You can compare item with different collations. For SQL Server you use :
table1.field1 = table2.field2 COLLATE FRENCH_CI_AS
or
table1.field1 = table2.field2 COLLATE SQL_Latin1_General_CP1_CI_AS
(or whatever the field1 collation is).
Note: You should try and leave the collation as the server default, unless you have a specific reason to do otherwise.
Is there any way to compare the generated range column in the mysql query ?
SELECT ue.bundle,ue.timestamp,b.id,bv.id as bundleVersionId,bv.start_date,bv.end_date, bv.type,ue.type from (
SELECT bundle,timestamp,tenant, case when Document_Id ='' then 'potrait'
WHEN Document_Id<>'' then 'persisted' end as type from uds_expanded ) ue
JOIN bundle b on b.name=ue.bundle join bundle_version bv on b.id=bv.bundle_id
WHERE ue.tenant='02306' and ue.timestamp >= bv.start_date and ue.timestamp <=bv.end_date and **ue.type=bv.type ;**
I am getting the following error when I try to compare the types
Error Code: 1267. Illegal mix of collations (utf8_general_ci,COERCIBLE) and (latin1_swedish_ci,IMPLICIT) for operation '=' 0.000 sec
Stick to one encoding/collation for your entire system. Right now you seem to be using UTF8 one place and latin1 in another place. Convert the latter to use UTF8 as well and you'll be good.
You can change the collation to UTF8 using
alter table <some_table> convert to character set utf8 collate utf8_general_ci;
I think sometimes the issue is we use different orm utilities to generate table and then we want to test queries either by mysql command line or MySql workbench, then this problem comes due to differences of table collation and the command line or app we use. simple way is to define your variables (ones used to test the query against table columns)
ex:
MySQL>
MySQL> set #testCode = 'test2' collate utf8_unicode_ci;
Query OK, 0 rows affected (0.00 sec)
MySQL> select * from test where code = #testCode;
full details
Be aware that the single columns can have their collation.
For example, Doctrine generates columns of VARCHAR type as CHARACTER SET utf8 COLLATE utf8_unicode_ci, and changing the table collation doesen't affect the single columns.
You can change the column's collation with this command:
ALTER TABLE `table`
CHANGE COLUMN `test` `test` VARCHAR(15) CHARACTER SET 'utf8' COLLATE 'utf8_general_ci'
or in MySql Workbench interface-> right click on the table-> Alter Table and then in the interface click on a column and modify it.
Use ascii_bin where ever possible, it will match up with almost any collation.
I have an InnoDB table in mysql with utf8 charset and utf8_general_ci collation.
After the following query:
SELECT * FROM `ticket`
WHERE `text` LIKE '%abc%'
ORDER BY `created_date` DESC
it returns me the rows containing "äbc" as well as containing "abc". I've tried to use utf8_bin collation on table, but it didn't helped.
What I've missed?
P.S. I thought that the problem is in the PHP connection charset, but after executing the query on Sequel Pro, I've got the same result.
for the unicode collation (both utf8_general_ci and utf8_unicode_ci) you have this kind of equalities:
Ä = A
Ö = O
Ü = U
this is not a bug.
read this http://dev.mysql.com/doc/refman/5.0/en/charset-unicode-sets.html and this http://dev.mysql.com/doc/refman/5.0/en/charset-collation-effect.html
Just got this answer from a previous question and it works a treat!
SELECT username, (SUM(rating)/COUNT(*)) as TheAverage, Count(*) as TheCount
FROM ratings WHERE month='Aug' GROUP BY username HAVING TheCount > 4
ORDER BY TheAverage DESC, TheCount DESC
But when I stick this extra bit in it gives this error:
Documentation #1267 - Illegal mix of
collations
(latin1_swedish_ci,IMPLICIT) and
(latin1_general_ci,IMPLICIT) for
operation '='
SELECT username, (SUM(rating)/COUNT(*)) as TheAverage, Count(*) as TheCount FROM
ratings WHERE month='Aug'
**AND username IN (SELECT username FROM users WHERE gender =1)**
GROUP BY username HAVING TheCount > 4 ORDER BY TheAverage DESC, TheCount DESC
The table is:
id, username, rating, month
Here's how to check which columns are the wrong collation:
SELECT table_schema, table_name, column_name, character_set_name, collation_name
FROM information_schema.columns
WHERE collation_name = 'latin1_general_ci'
ORDER BY table_schema, table_name,ordinal_position;
And here's the query to fix it:
ALTER TABLE tbl_name CONVERT TO CHARACTER SET latin1 COLLATE 'latin1_swedish_ci';
Link
Check the collation type of each table, and make sure that they have the same collation.
After that check also the collation type of each table field that you have use in operation.
I had encountered the same error, and that tricks works on me.
[MySQL]
In these (very rare) cases:
two tables that really need different collation types
values not coming from a table, but from an explicit enumeration, for instance:
SELECT 1 AS numbers UNION ALL SELECT 2 UNION ALL SELECT 3
you can compare the values between the different tables by using CAST or CONVERT:
CAST('my text' AS CHAR CHARACTER SET utf8)
CONVERT('my text' USING utf8)
See CONVERT and CAST documentation on MySQL website.
I was getting this same error on PhpMyadmin and did the solution indicated here which worked for me
ALTER TABLE table CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci
Illegal mix of collations MySQL Error
Also I would recommend going with General instead of swedish since that one is default and not to use the language unless your application is using Swedish.
I think you should convert to utf8
--set utf8 for connection
SET collation_connection = 'utf8_general_ci'
--change CHARACTER SET of DB to utf8
ALTER DATABASE dbName CHARACTER SET utf8 COLLATE utf8_general_ci
--change CHARACTER SET of table to utf8
ALTER TABLE tableName CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci
I also got same error, but in my case main problem was in where condition the parameter that i'm checking was having some unknown hidden character (+%A0)
When A0 convert I got 160 but 160 was out of the range of the character that db knows, that's why database cannot recognize it as character other thing is my table column is varchar
the solution that I did was I checked there is some characters like that and remove those before run the sql command
ex:- preg_replace('/\D/', '', $myParameter);
Check that your users.gender column is an INTEGER.
Try: alter table users convert to character set latin1 collate latin1_swedish_ci;
You need to change each column Collation from latin1_general_ci to latin1_swedish_ci
I got this same error inside a stored procedure, in the where clause. i discovered that the problem ocurred with a local declared variable, previously loaded by the same table/column.
I resolved it casting the data to single char type.
In short, this error is caused by MySQL trying to do an operation on two things which have different collation settings. If you make the settings match, the error will go away. Of course, you need to choose the right setting for your database, depending on what it is going to be used for.
Here's some good advice on choosing between two very common utf8 collations: What's the difference between utf8_general_ci and utf8_unicode_ci
If you are using phpMyAdmin you can do this systematically by working through the tables mentioned in your error message, and checking the collation type for each column. First you should check which is the overall collation setting for your database - phpMyAdmin can tell you this and change it if necessary. But each column in each table can have its own setting. Normally you will want all these to match.
In a small database this is easy enough to do by hand, and in any case if you read the error message in full it will usually point you to the right place. Don't forget to look at the 'structure' settings for columns with subtables in as well. When you find a collation that does not match you can change it using phpMyAdmin directly, no need to use the query window. Then try your operation again. If the error persists, keep looking!
The problem here mainly, just Cast the field like this cast(field as varchar) or cast(fields as date)
I had this problem not because I'm storing in different collations, but because my column type is JSON, which is binary.
Fixed it like this:
select table.field COLLATE utf8mb4_0900_ai_ci AS fieldName
Use ascii_bin where ever possible, it will match up with almost any collation.
A username seldom accepts special characters anyway.
If you want to avoid changing syntax to solve this problem, try this:
Update your MySQL to version 5.5 or greater.
This resolved the problem for me.
I have the same problem with collection warning for a field that is set from 0 to 1. All columns collections was the same. We try to change collections again but nothing fix this issue.
At the end we update the field to NULL and after that we update to 1 and this overcomes the collection problem.
Was getting Illegal mix of collations while creating a category in Bagisto. Running these commands (thank you #Quy Le) solved the issue for me:
--set utf8 for connection
SET collation_connection = 'utf8_general_ci'
--change CHARACTER SET of DB to utf8
ALTER DATABASE dbName CHARACTER SET utf8 COLLATE utf8_general_ci
--change category tables
ALTER TABLE categories CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci
ALTER TABLE category_translations CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci
In my case it was something strange. I read an api key from a file and then I send it to the server where a SQL query is made. The problem was the BOM character that the Windows notepad left, it was causing the error that says:
SQLSTATE[HY000]: General error: 1267 Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8_general_ci,COERCIBLE) for operation '='
I just removed it and everything worked like a charm
You need to set 'utf8' for all parameters in each Function. It's my case:
SELECT username, AVG(rating) as TheAverage, COUNT(*) as TheCount
FROM ratings
WHERE month='Aug'
AND username COLLATE latin1_general_ci IN
(
SELECT username
FROM users
WHERE gender = 1
)
GROUP BY
username
HAVING
TheCount > 4
ORDER BY
TheAverage DESC, TheCount DESC;
Make sure your version of MySQL supports subqueries (4.1+). Next, you could try rewriting your query to something like this:
SELECT ratings.username, (SUM(rating)/COUNT(*)) as TheAverage, Count(*) as TheCount FROM ratings, users
WHERE ratings.month='Aug' and ratings.username = users.username
AND users.gender = 1
GROUP BY ratings.username
HAVING TheCount > 4 ORDER BY TheAverage DESC, TheCount DESC