How to use sql datetime

The DATETIME data type is used to store high-precision date and time information, ranging from 0001-01-01 00:00:00 to 9999-12-31 23:59:59.99999999, and the syntax is DATETIME(precision), where precision specifies the accuracy after the decimal point (0-7), and the default is 3. It supports sorting, calculation, and time zone conversion functions, but needs to be aware of potential issues when converting precision, range and time zones.

SQL DATETIME Data Type

What is the DATETIME data type?

DATETIME data type is used to store date and time information. It is a high-precision type that can store date and time values ​​from 0001-01-01 00:00:00 to 9999-12-31 23:59:59.9999999999.

grammar

The syntax for declaring a DATETIME data type is as follows:

 <code class="sql">DATETIME(precision)</code>

Where precision specifies the accuracy after the decimal point (0-7), indicating the number of digits in milliseconds. If precision is omitted, the default is 3.

How to use

To use the DATETIME data type, you can use the following methods:

• Specify when creating a table:

   <code class="sql">CREATE TABLE my_table ( datetime_col DATETIME );</code>

• Insert data into the table:

   <code class="sql">INSERT INTO my_table (datetime_col) VALUES ('2023-03-08 12:34:56');</code>

Function

The DATETIME data type provides the following features:

• Accuracy: Can store date and time values ​​in milliseconds.
• Sort: Supports sorting based on date and time.
• Calculation: Allows arithmetic operations of date and time, such as addition and subtraction.
• Time zone support: By using the time zone conversion function, date and time values ​​of different time zones can be processed.

Things to note

When using DATETIME data types, you need to pay attention to the following:

• Decimal point accuracy: The accuracy should be set according to actual needs, as higher accuracy consumes additional storage space.
• Range: Date and time values ​​must be within the specified range.
• Time zone conversion: Time zone conversion may involve data loss or duplication and therefore needs to be handled with caution.

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