MySQL SELECT query. Description, application and functions

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• select distinct `first_name` from `ex_workers` where `first_name` like '%%'"
• select distinct `first_name` from `ex_workers` where `First_name` like '%%'"

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• select `first_name`, `last_name`, `w_status` from `ex_workers`;
• select distinct `w_status` from `ex_workers`;
• select distinct `start_timestamp` from `ex_workers` where `start_timestamp`!= '0000-00-00 00:00:00';
• select distinct `start_timestamp` from `ex_workers` where (`start_timestamp`!= '0000-00-00 00:00:00') and start_timestamp > '2017-12-05 09:00:00'.

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Strict adherence to MySQL select syntax rules is a good rule: practical, safe, efficient. But if we restrict ourselves to its application at the level of each database object, and work directly with these objects according to their methods (their rules), the efficiency will increase many times.