SQLite 3.16

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CREATE TABLE entry(input TEXT);

INSERT INTO entry(input)
VALUES ('help'),('help text'),('text help text'),
('help (help)'),('(help) help'),('(help) text'),
('text (help)'),('(help text)'),
('help {help}'),('{help} help'),('{help} text'),
('text {help}'),('{help text}'),
('help [help]'),('[help] help'),('[help] text'),
('text [help]'),('[help text]');
SELECT * FROM entry

input

help

help text

text help text

help (help)

(help) help

(help) text

text (help)

(help text)

help {help}

{help} help

{help} text

text {help}

{help text}

help [help]

[help] help

[help] text

text [help]

[help text]

SELECT * FROM entry
WHERE input LIKE 'help%'
OR input LIKE '%help'
OR input LIKE '%help%'
AND input NOT LIKE '%(%help%)%'
AND input NOT LIKE '%{%help%}%'
AND input NOT LIKE '%[%help%]%'
   
input

help

help text

text help text

help (help)

(help) help

help {help}

{help} help

help [help]

[help] help