Comments - About the Knowledge Base

I have found that the syntax in the documentation contains allot of closed brackets, and I'm wondering what all of that means. For example,

 LOAD DATA [LOW_PRIORITY | CONCURRENT] [LOCAL] INFILE 'file_name'
    [REPLACE | IGNORE]
    INTO TABLE tbl_name
    [CHARACTER SET charset_name]
    [{FIELDS | COLUMNS}
        [TERMINATED BY 'string']
        [[OPTIONALLY] ENCLOSED BY 'char']
        [ESCAPED BY 'char']
    ]
    [LINES
        [STARTING BY 'string']
        [TERMINATED BY 'string']
    ]
    [IGNORE number LINES]
    [(col_name_or_user_var,...)]
    [SET col_name = expr,...]

I have not found a document that explains the conventions used in the documentation, particularly the knowledge base articles.

[..] means that the contents are optional, and | means OR. So, in your example, you can use LOAD DATA LOW PRIORITY... or LOAD DATA CONCURRENT..., or neither option, just LOAD DATA...

You're right that there should be a key - these are standard conventions, but should still be explained.