drop table if exists t1; show variables like "ft\_%"; Variable_name Value ft_boolean_syntax + -><()~*:""&| ft_max_word_len 84 ft_min_word_len 4 ft_query_expansion_limit 20 ft_stopword_file (built-in) create table t1 (b text not null); insert t1 values ('aaaaaa bbbbbb cccccc'); insert t1 values ('bbbbbb cccccc'); insert t1 values ('aaaaaa cccccc'); select * from t1 where match b against ('+aaaaaa bbbbbb' in boolean mode); b aaaaaa bbbbbb cccccc aaaaaa cccccc set ft_boolean_syntax=' +-><()~*:""&|'; ERROR HY000: Variable 'ft_boolean_syntax' is a GLOBAL variable and should be set with SET GLOBAL set global ft_boolean_syntax=' +-><()~*:""&|'; select * from t1 where match b against ('+aaaaaa bbbbbb' in boolean mode); b aaaaaa bbbbbb cccccc bbbbbb cccccc set global ft_boolean_syntax='@ -><()~*:""&|'; select * from t1 where match b against ('+aaaaaa bbbbbb' in boolean mode); b aaaaaa bbbbbb cccccc bbbbbb cccccc aaaaaa cccccc select * from t1 where match b against ('+aaaaaa @bbbbbb' in boolean mode); b aaaaaa bbbbbb cccccc bbbbbb cccccc set global ft_boolean_syntax='@ -><()~*:""@|'; ERROR 42000: Variable 'ft_boolean_syntax' can't be set to the value of '@ -><()~*:""@|' set global ft_boolean_syntax='+ -><()~*:""@!|'; ERROR 42000: Variable 'ft_boolean_syntax' can't be set to the value of '+ -><()~*:""@!|' drop table t1;