Here are three options for returning rows that contain lowercase characters in SQLite.

Sample Data

Suppose we have a table with the following data:

.nullvalue null
SELECT c1 FROM t1;

Result:

c1            
--------------
CAFÉ          
Café          
café          
1café         
eCafé         
James Bond 007
JB 007        
007           
null          
              
É             
É 123         
é             
é 123         
ø             
Ø             

We can use the following methods to return the rows that contain lowercase letters.

Option 1: Compare to the UPPER() String

We can use the UPPER() function to compare the original value to its uppercase equivalent:

SELECT c1 FROM t1
WHERE UPPER(c1) <> c1;

Result:

c1            
--------------
Café          
café          
1café         
eCafé         
James Bond 007

By using the not equal to (<>) operator (you can alternatively use != instead of <> if you prefer), we only return those rows that are different to their uppercase equivalents. The reason we do this is because, if a value is the same as its uppercase equivalent, then it was already uppercase to begin with (and we don’t want to return it).

SQLite performs a case-sensitive search, and so we don’t need to do anything else to get the result we desire.

You might have noticed that the above example didn’t return the lowercase unicode characters é and ø unless the value also included a non-unicode lowercase letter. SQLite does not fully support unicode characters. For example, the UPPER() and LOWER() functions only provide case mapping for the 26 letters used in the English language. Therefore, the above example didn’t convert any unicode characters to their uppercase equivalent.

Take a look at the SQLite ICU extension if you need to work with unicode characters.

Option 2: Compare to the Actual Characters

Another option is to use the REGEXP operator with a regular expression pattern that explicitly includes each lowercase character we want to match:

SELECT c1 FROM t1
WHERE c1 REGEXP '[abcdefghijklmnopqrstuvwxyz]';

Result:

c1            
--------------
Café          
café          
1café         
eCafé         
James Bond 007

We can include unicode characters in our list if we wish:

SELECT c1 FROM t1
WHERE c1 REGEXP '[éøabcdefghijklmnopqrstuvwxyz]';

Result:

c1            
--------------
Café          
café          
1café         
eCafé         
James Bond 007
é             
é 123         
ø             

Option 3: Compare to a Range of Characters

Another way to do it is to specify the range of lowercase characters we want to match:

SELECT c1 FROM t1
WHERE c1 REGEXP '[a-z]';

Result:

c1            
--------------
Café          
café          
1café         
eCafé         
James Bond 007