In order not to scan the entire table, indexes are of course necessary. Otherwise, how do we know that the ctime in other data must not be greater than the found pieces of data. As for MySQL, how do you know it has not scanned the entire table? MySQL's data storage is compact, and its scanning speed is much faster than Mongo. Therefore, MySQL has an advantage in the absence of indexes.
One of the advantages of Mongo is its rich query methods, and to demonstrate this feature of Mongo, reasonable and necessary indexes are indispensable.
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In order not to scan the entire table, indexes are of course necessary. Otherwise, how do we know that the ctime in other data must not be greater than the found pieces of data. As for MySQL, how do you know it has not scanned the entire table? MySQL's data storage is compact, and its scanning speed is much faster than Mongo. Therefore, MySQL has an advantage in the absence of indexes.
One of the advantages of Mongo is its rich query methods, and to demonstrate this feature of Mongo, reasonable and necessary indexes are indispensable.