If I have a table with a column called TITLE which contains text of mixed case, e.g.
Vinashin to Receive Government Loans to Pay Workers
German government concerned over rise in inflation
Is it possible to perform an SQL LIKE query such as:
SELECT * FROM MYTABLE WHERE TITLE LIKE '%Government%'
But which would only return the first row and not the second?
MYSQL's LIKE seems to ignore case.
From the documentation:
The following two statements illustrate that string comparisons are not case sensitive unless one of the operands is a binary string:
mysql> SELECT 'abc' LIKE 'ABC';
-> 1
mysql> SELECT 'abc' LIKE BINARY 'ABC';
-> 0
So you can use LIKE BINARY '%Government%' to make a case-sensitive comparison.
You can use:
LIKE BINARY
instead of LIKE and it will match case sensitive.
Related
I am a beginner so please help me.
There are 2 things you need to combine in this case.
Because you didn't provide enough information in your question we have to guess what you mean by name. I'm going to assume that you have a single name column, but that would be unusual.
With strings, to match a character column that is not an exact match, you need to use LIKE which allows for wildcards.
You also need to negate the match, or in other words show things that are NOT (something).
First to match names that START with 'A'.
SELECT * FROM table_name WHERE name LIKE 'A%';
This should get you all the PEOPLE who have names that "Start with A".
Some databases are case sensitive. I'm not going to deal with that issue. If you were using MySQL that is not an issue. Case sensitivity is not universal. In some RDBMS like Oracle you have to take some steps to deal with mixed case in a column.
Now to deal with what you actually want, which is NOT (starting with A).
SELECT * FROM table_name WHERE name NOT LIKE 'A%';
your question should have more detail however you can use the substr function
SELECT name FROM yourtable
WHERE SUBSTR(name,1,1) <> 'A'
complete list of mysql string functions here
mysql docs
NOT REGXP operator
MySQL NOT REGXP is used to perform a pattern match of a string expression expr against a pattern pat. The pattern can be an extended regular expression.
Syntax:
expr NOT REGEXP pat
Query:
SELECT * FROM emp_table WHERE emp_name NOT REGEXP '^[a]';
or
SELECT * FROM emp_table WHERE emp_name NOT REGEXP '^a';
I am trying to execute the sql query:
select * from table where column like '%value%';
But the data is saved as 'Value' ( V is capital ).
When I execute this query i don't get any rows.
How do i make the call such that, it looks for 'value' irrespective of the casing of the characters ?
use LOWER Function in both (column and search word(s)). Doing it so, you assure that the even if in the query is something like %VaLuE%, it wont matter
select qt.*
from query_table qt
where LOWER(column_name) LIKE LOWER('%vAlUe%');
If you want this column be case insensitive :
ALTER TABLE `schema`.`table`
CHANGE COLUMN `column` `column` TEXT CHARACTER SET 'utf8' COLLATE 'utf8_general_ci';
Thus, you don't have to change your query.
And the MySQL engine will process your query quicker than using lower() function or any other tricks.
And I'm not sure that using lower function will be a good solution for index searching performance.
Either use a case-insensitive collation on your table, or force the values to be lower case, e.g.
WHERE lower(column) LIKE lower('%value%');
Try using a case insensitive collation
select * from table
where column like '%value%' collate utf8_general_ci
Use the lower() function:
select t.*
from table t
where lower(column) like '%value%';
you should use either lower or upper function to ignore the case while you are searching for some field using like.
select * from student where upper(sname) like 'S%';
OR
select * from student where lower(sname) like 'S%';
If you are using PostgreSQL, a simpler solution is to use insensitive like (ILIKE):
SELECT * FROM table WHERE column ILIKE '%value%'
I know this is a very old question, but I'm posting this for posterity:
Non-binary string comparisons (including LIKE) are case-insensitive by default in MySql:
https://dev.mysql.com/doc/refman/en/case-sensitivity.html
This will eventually do the same thing. The ILIKE works, irrespective of the casing nature
SELECT *
FROM table
WHERE column_name ILIKE "%value%"
Can't seem to find documentation on a particular formation of SQL using the LIKE operator. Using MySQL, a typical query for multiple words using the LIKE operator may look like this:
SELECT * from table AS t WHERE t.col LIKE '%word1%' AND t.col LIKE '%word2%'
Although the following statement also works, the rows returned will vary depending on the order of the words in the query. For example:
SELECT * from table WHERE col LIKE '%word1%' '%word2%'
executes without the AND boolean, but with different results from:
SELECT * from table WHERE col LIKE '%word2%' '%word1%'
My question is, what is actually happening when using this formation of the query instead of using boolean?
From the manual:
Quoted strings placed next to each other are concatenated to a single
string. The following lines are equivalent:
'a string'
'a' ' ' 'string'
So, what's happening is that '%word1%' '%word2%' is being interpreted as '%word1%%word2%'
In my table I have firstname and last name. Few names are upper case ( ABRAHAM ), few names are lower case (abraham), few names are character starting with ucword (Abraham).
So when i am doing the where condition using REGEXP '^[abc]', I am not getting proper records. How to change the names to lower case and use SELECT QUERY.
SELECT * FROM `test_tbl` WHERE cus_name REGEXP '^[abc]';
This is my query, works fine if the records are lower case, but my records are intermediate ,my all cus name are not lower case , all the names are like ucword.
So for this above query am not getting proper records display.
I think you should query your database making sure that the names are lowered, suppose that name is the name you whish to find out, and in your application you've lowered it like 'abraham', now your query should be like this:
SELECT * FROM `test_tbl` WHERE LOWER(cus_name) = name
Since i dont know what language you use, I've just placed name, but make sure that this is lowered and you should retrieve Abraham, ABRAHAM or any variation of the name!
Hepe it helps!
Have you tried:
SELECT * FROM `test_tbl` WHERE LOWER(cus_name) REGEXP '^[abc]';
I don't know since when, but nowadays MySql REGEXP is case insensitive.
https://dev.mysql.com/doc/refman/5.7/en/pattern-matching.html
You don't need regexp to search for names starting with a specific string or character.
SELECT * FROM `test_tbl` WHERE cus_name LIKE 'abc%' ;
% is wildcard char. The search is case insensitive unless you set the binary attribute for column cus_name or you use the binary operator
SELECT * FROM `test_tbl` WHERE BINARY cus_name LIKE 'abc%' ;
A few valid options already presented, but here's one more with just regex:
SELECT * FROM `test_tbl` WHERE cus_name REGEXP '^[abcABC]';
First off, I recognize the differences between the two:
- Like makes available the wildcards % and _
- significant trailing whitespace
- colation issues
All other things being equal, for an exact string match which is more efficient:
SELECT field WHERE 'a' = 'a';
Or:
SELECT field WHERE 'a' LIKE 'a';
Or: Is the difference so insignificant that it doesn't matter?
I would say that the = comparator would be faster. The lexical doesn't send the comparison to another lexical system to do general matches. Instead the engine is able to just match or move on. Our db at work has millions of rows and an = is always faster.
In a decent DBMS, the DB engine would recognise that there were no wildcard characters in the string and implicitly turn it into a pure equality (not necessarily the same as =). So, you'd only get a small performance hit at the start, usually negligible for any decent-sized query.
However, the MySQL = operator doesn't necessarily act the way you'd expect (as a pure equality check). Specifically, it doesn't by default take into account trailing spaces for CHAR and VARCHAR data, meaning that:
SELECT age WHERE name = 'pax'
will give you rows for 'pax', 'pax<one space>' and 'pax<a hundred spaces>'.
If you want to do a proper equality check, you use the binary keyword:
SELECT field WHERE name = binary 'pax'
You can test this with something like:
mysql> create table people (name varchar(10));
mysql> insert into people value ('pax');
mysql> insert into people value ('pax ');
mysql> insert into people value ('pax ');
mysql> insert into people value ('pax ');
mysql> insert into people value ('notpax');
mysql> select count(*) from people where name like 'pax';
1
mysql> select count(*) from people where name = 'pax';
4
mysql> select count(*) from people where name = binary 'pax';
1