begins with comienza con field REGEXP '^~' does not begin with no comienza con field not REGEXP '^-?\'?(~)' ends with termina con field REGEXP '~$' does not end with no termina con field not REGEXP '(~)$|~[ ,.?!]+~' contains sequence contiene secuencia field REGEXP '~' does not contain sequence no contiene secuencia field NOT REGEXP '~' equals es igual a field REGEXP '^~$' does not equal no es igual a field not REGEXP '^~$' empty vacío field = '' not empty no vacío field <> '' contains word contiene palabra field REGEXP '[[:<:]]~[[:>:]]' does not contain word no contiene palabra field NOT REGEXP '[[:<:]]~[[:>:]]' regular expression expresión regular ~