date usage in oracle

The DATE data type stores date values ​​that do not contain time information. Its uses include saving date information, date operations, and data type conversion. Example usages include: calculating date intervals, comparing dates, and extracting date components. Note that the DATE type does not store time zone information, which ranges from January 1, 4712 BC to December 31, 9999 AD.

DATE data type in Oracle

The DATE data type is used to represent date values ​​in Oracle database, which stores is a specific date and does not contain time information. The syntax is as follows:

<code>DATE</code>

Usage of DATE data type

• Save date information:Can be used to store date values ​​that do not contain time information , such as birthday or contract expiry date.

• Date operations: Oracle provides many functions and operators to calculate DATE values, such as:

  • Addition ( ) and subtraction ( -): Can be used to calculate the interval between dates.
  • Comparison operators (<, >, =, <=, >=): can be used to compare two dates.
  • Date function: Provides functions such as obtaining days, months and years.
• Data type conversion: DATE type can be converted with other data types (such as VARCHAR2, NUMBER) for data manipulation or display.

Example

<code class="sql">-- 创建一个包含日期值的表
CREATE TABLE dates (
  date_column DATE
);

-- 插入数据
INSERT INTO dates VALUES ('2023-03-08');

-- 查询日期值
SELECT date_column FROM dates;

-- 计算日期之间的间隔
SELECT date_column + 10 FROM dates;</code>

Notes

• DATE type ranges from 4712 BC 1 From January 1st to December 31st, 9999 AD.
• The DATE type does not store time zone information.
• Values ​​of type DATE are represented by an Oracle internal format and need to be formatted for display or conversion using the TO_CHAR() function.

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