How to convert oracle date to string

Oracle database is a common relational database management system with a wide range of application fields. In Oracle, date data can be stored directly in the database and supports multiple date formats. If we need to convert Oracle's date data type to a string type, we can use the date formatting function provided by Oracle to achieve this.

1. TO_CHAR function

In Oracle, you can use the TO_CHAR function to convert the date type to a string type. The syntax is as follows:

TO_CHAR(date, format)

Among them, date represents the date to be converted, and format represents the converted date format. For example, to convert a date type to a string in YYYY-MM-DD format, you can use the following statement:

SELECT TO_CHAR(SYSDATE, 'YYYY-MM-DD') FROM dual;

In the above statement, SYSDATE represents the current date of the system, and dual represents a virtual table, which can be used to test SQL statements in Oracle. Executing the above statement will return the string form of the current date, for example:

2019-12-04

2. Date formatting symbol

in the TO_CHAR function , you can use a series of date formatting symbols to define the converted date format. Here are some commonly used date formatting symbols and their meanings:

• YYYY: 4-digit year
• YY: 2-digit year
• MM: Month (01-12)
• MON: Abbreviated month name
• MONTH: Month name
• DD: Date (01-31)
• D: Date (1-31)
• DAY: abbreviated day of the week
• DY: day of the week
• DAYNAME: full name of day of the week
• HH24: hour in 24-hour format Number (00-23)
• HH: Number of hours in 12-hour format (01-12)
• MI: Number of minutes (00-59)
• SS: Number of seconds ( 00-59)
• AM/PM: AM/PM mark
• TZD: Time zone offset

For example, to format the date as "YYYYMM "Month DD day HH24:MI:SS" string, you can use the following statement:

SELECT TO_CHAR(SYSDATE, 'YYYY"Year"MM"Month"DD"Day" HH24:MI:SS') FROM dual;

In the above statement, use double quotation marks to include Chinese characters to prevent them from being used as formatting symbols.

3. Date type conversion

In Oracle, conversion between date data type and character data type can be achieved through the TO_CHAR and TO_DATE functions. The TO_CHAR function can convert date type to character type, and the TO_DATE function can convert character type to date type. For example, to convert the string "2019-12-04" to a date type, you can use the following statement:

SELECT TO_DATE('2019-12-04', 'YYYY-MM-DD') FROM dual ;

In the above statement, the first parameter represents the string to be converted, and the second parameter represents the date format of the string.

It should be noted that when converting date type and character type, the formatting symbols must be consistent, otherwise a conversion error will occur.

4. Summary

This article introduces the method of converting date type data into string type in Oracle, mainly involving the use of TO_CHAR function and date formatting symbols. By studying this article, readers can master the conversion methods between date types and character types, and learn how to customize the date format as needed.

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