How is the cast function used in Oracle?

2 years ago
Isabella Edwards
2 minutes

The CAST function in Oracle is used to convert an expression into a specified data type. Its syntax is as follows:

Convert the expression to the specified datatype.

“Where expression is the expression to be converted, and datatype is the data type to be converted to.”

I am sorry, I don’t understand what you are asking for.

  1. Convert the expression of character type to a number type:
    SELECT CAST(‘123’ AS NUMBER) FROM dual;
    The result is 123.
  2. Convert date expression to character type:
    SELECT TO_CHAR(SYSDATE, ‘YYYY-MM-DD’) FROM dual;
    Gives the current date in string format, such as ‘2022-01-01’.
  3. Convert an expression of character type to a date type:
    SELECT CAST(‘2022-01-01’ AS DATE) FROM dual;
    The result is a value of date type, which is the date ‘2022-01-01’.

It is important to note that the CAST function throws an exception when the conversion fails, so it is necessary to ensure that the expression and target data type are compatible when using it. Additionally, Oracle also provides other type conversion functions similar to the CAST function, such as TO_CHAR, TO_NUMBER, TO_DATE, etc. Choose the appropriate function based on specific requirements.

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