How to convert numbers to characters in oracle

Oracle is a powerful database management system. In this system, conversion of numbers and characters is a frequently required operation. In this article, we will explore Oracle's methods of converting numbers to characters.

1. Use the TO_CHAR function

In Oracle, you can use the TO_CHAR function to convert numbers into characters. The syntax of this function is as follows:

TO_CHAR (number, [format_mask], [nls_language])

The parameter number is the number to be converted, which can be an integer or a decimal. The parameter format_mask is optional and defines the format of the return value. The parameter nls_language is also optional and defines the character set and language.

Here are some examples:

1. Convert numbers to strings

SELECT TO_CHAR(12345) FROM DUAL;

Output results For: '12345'

2. Convert the number to currency format

SELECT TO_CHAR(12345.67, '$99999.99') FROM DUAL;

The output result is : '$12345.67'

3. Convert the number to scientific notation

SELECT TO_CHAR(12345.67, '9.99E999') FROM DUAL;

Output result For: '1.23E 004'

4. Convert the number to Roman numerals

SELECT TO_CHAR(1234, 'RN') FROM DUAL;

Output The result is: 'MCCXXXIV'

5. Convert numbers to Chinese numbers

SELECT TO_CHAR(123456, 'CHINESE') FROM DUAL;

Output result It is: 'One hundred and twenty-three thousand four hundred and fifty-six'

2. Use the CAST function

In Oracle, you can use the CAST function to convert numbers into characters. The syntax of this function is as follows:

CAST (expression AS data_type)

The parameter expression is the number to be converted, which can be an integer or a decimal. The parameter data_type is the character type to be converted, such as VARCHAR2, CHAR, CLOB, etc.

Here are some examples:

1. Convert number to string

SELECT CAST(12345 AS VARCHAR2(10)) FROM DUAL;

The output result is: '12345'

2. Convert the number to currency format

SELECT CAST(12345.67 AS VARCHAR2(10)) FROM DUAL;

The output result is: '12345.67'

3. Convert the number to scientific notation

SELECT CAST(12345.67 AS VARCHAR2(10)) FROM DUAL;

The output result is: '1.23457E 04'

4. Convert the number to Roman numerals

SELECT CAST(1234 AS VARCHAR2(5)) FROM DUAL;

The output result is: 'MCCXXXIV'

5. Convert numbers to Chinese numbers

You cannot use the CAST function to directly convert numbers to Chinese numbers.

3. Use CHR and ASCII functions

In Oracle, you can use the CHR function to convert numbers into characters. The syntax of this function is as follows:

CHR (number)

The parameter number is the number to be converted, which is an integer. It will be converted into the corresponding ASCII character.

In Oracle, you can use ASCII functions to convert characters into numbers. The syntax of this function is as follows:

ASCII (char)

The parameter char is the character to be converted, which is a single-character string. It will be converted into the corresponding ASCII code number.

Here are some examples:

1. Convert number to string

SELECT CHR(49) || CHR(50) || CHR(51 ) || CHR(52) || CHR(53) FROM DUAL;

The output result is: '12345'

2. Convert the number to currency format

You cannot use the CHR function to convert a number directly to currency format.

3. Convert a number to scientific notation

You cannot use the CHR function to convert a number directly to scientific notation.

4. Convert numbers to Roman numerals

You cannot use the CHR function to convert numbers directly to Roman numerals.

5. Convert numbers to Chinese numbers

You cannot use the CHR function to convert numbers directly to Chinese numbers.

Summary

In Oracle, the conversion of numbers and characters is a common but very important task. In this article, we introduced the use of TO_CHAR function, CAST function, CHR function and ASCII function to achieve conversion between numbers and characters. Whether you need to convert a number to currency format, scientific notation, Roman numerals, or Chinese numerals, you can do it using these functions.

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