Let’s try creating one such table which has automatic initialization as well as updation. All subsequent updates to the row would result in updating the field updated_time with the current system time. Please note that, during the time of row insertion, both created_time and updated_time would have the same value. What this means is generally tables have 2 columns like – created_time and updated_time.Ĭreated_time column is configured to take the value of the current system time whenever the row is inserted, and similarly updated_time is configured to take the current system time whenever there are any updates done to a particular row of the table. In the real-life scenarios – most of the time, the DATETIME initialization and updates are configured to be automatic. Depending upon the number of fractional digits specified, the fractional values are captured and displayed.Īutomatic Initialization and Updation of DATETIME and TIMESTAMP Fields
now() function returns the current datetime in the format – dd:mm:yyyy hh:mm:ss.All columns got assigned values per the data types, for example, for the first column – YEAR – though we inserted using ‘now()’ function which is the current timestamp, the value that got inserted is just the year part of the current date time – i.e.Now, let’s see the contents of the table to analyze the data in different columns. insert into datetime_illustration values (now(), now(), now(), now(), now(), now(), now(), now()) Notice how using this function would result in trimming/inserting only the required part of the current date and time, depending on the data type of the column. Insert a single row in the table using the ‘now()’ function, which is the current timestamp. Timestamp_col TIMESTAMP, timestamp_col_fractional TIMESTAMP(6)) Time_col_fractional TIME(2), datetime_col DATETIME, datetime_col_fractional DATETIME(6), CREATE TABLE datetime_illustration(year_col YEAR, date_col DATE, time_col TIME, Let’s illustrate all these data types as part of a single table and see the values that are assigned to each of the types. Then total memory used would be => memory used by TIME data type + memory used by 5 fractional component => 3 + 3 => 6 bytes
Using the above table, for example, if we have a column type as – TIME(5). Now we will understand the memory requirements for fractional-storage. For TIME, DATETIME, and TIMESTAMP data types depending on the fractional component specified, the memory consumed would be different. Let’s try to understand these briefly in the below table, before diving deeper into DATE FORMATS and DATETIME FUNCTIONS provided by MySQL. – YEAR, DATE, TIME, DATETIME, and TIMESTAMP. MySQL stores date and time values using 5 different data types i.e. DATE And TIME Data Typesĭata types include YEAR, DATE, TIME, DATETIME, and TIMESTAMP. => For installing MySQL refer to our tutorial here. Pre-Requisitesįor running the examples used in the tutorial, you would need a local setup of MySQL installation. These functions are very important whenever any operations on date time column values are required in MySQL tables. #4) Fetching Specific Parts Of DateTime Columns.