Feeding this SQL to the Parser:

SELECT
 CASE 
 WHEN a.kol = 1 THEN 'one'
 ELSE a.kol
 END as 'case'
FROM foo a;

will result in errors, and calling build() on the statement will result in this SQL:

SELECT CASE 'case' ELSE a.kol AS `END` END FROM foo AS `a`

The errors array contains these errors:

• An alias was previously found.
• An alias was expected.
• Unexpected keyword.
• Unexpected end of CASE expression

I encountered this problem since I upgraded from 5.8.2 to 5.9.1.