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Another option (relevant for version 5.7.3 and above) is to create a generated/virtual column based on the datetime column, then index it. CREATE TABLE `table` ( `my_datetime` datetime NOT NULL, `my_date` varchar(12) GENERATED ALWAYS AS (DATE(`my_datetime`)) STORED, KEY `my_idx` (`my_date`) ) ENGINE=InnoDB;
But, when comparing NOT NULL and NULL, it seems that MySQL preferrs other indexes when using NOT NULL. Although this does obviously not add any information. This is because MySQL interprets NOT NULL as a range as you can see in type-column. I'm not sure If there is a workaround:
Here is an example that uses date functions. The following query selects all rows with a date_col value from within the last 30 days: . mysql> SELECT something FROM tbl_name-> WHERE DATE_SUB(CURDATE(),INTERVAL 30 DAY) <= date_col;. The query also selects rows with dates that lie in the future.
To query the index information of a table, you use the SHOW INDEXES statement as follows: SHOW INDEXES FROM table_name; Code language: SQL (Structured Query Language) (sql) To get the index of a table, you specify the table name after the FROM keyword.
1 wrz 2016 · If the table has an index on the x column, then the database server can perform a range scan on the index. That means it can quickly find the first relevant value of x, and then scan the index sequentially until it finds the last relevant value.
SQL Date Data Types. MySQL comes with the following data types for storing a date or a date/time value in the database: DATE - format YYYY-MM-DD; DATETIME - format: YYYY-MM-DD HH:MI:SS; TIMESTAMP - format: YYYY-MM-DD HH:MI:SS; YEAR - format YYYY or YY; SQL Server comes with the following data types for storing a date or a date/time value in the ...
You can use a NULL value in the INSERT statement to specify that the data is missing. For example, the following statement inserts a row into the leads table. Because the phone number is missing, so a NULL value is used. INSERT INTO leads(first_name,last_name, source,email,phone)
