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Description

The ORA-30077 error occurs in Oracle Database when attempting an invalid implicit or explicit cast between incompatible datetime datatypes. This often happens within SQL queries or PL/SQL blocks when Oracle cannot automatically convert between the specified datetime types.

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Error Message

ORA-30077: illegal casting between specified datetime types

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Known Causes

3 known causes

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Incompatible Datatypes

Attempting to cast between fundamentally different datetime types like DATE and TIMESTAMP without proper conversion functions will result in this error. 💻

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Missing Timezone Conversion

Casting between TIMESTAMP WITH TIME ZONE and TIMESTAMP without considering timezone differences can lead to failure. 🌐

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Incorrect Format Masks

Using incorrect or missing format masks in TO_CHAR or TO_DATE functions when converting datetime values can cause casting issues. ⚙

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Solutions

3 solutions available

1. Explicitly Cast to a Compatible Datetime Type easy

Ensure both source and target datetime types are compatible or explicitly cast them.

1

Identify the exact datetime types involved in the casting operation. This often occurs when trying to convert between `DATE`, `TIMESTAMP`, `TIMESTAMP WITH TIME ZONE`, or `TIMESTAMP WITH LOCAL TIME ZONE`.

2

If you are trying to cast a `DATE` to a `TIMESTAMP`, use `TO_TIMESTAMP` or `TO_TIMESTAMP_TZ`. If you are trying to cast a `TIMESTAMP` to a `DATE`, be aware that fractional seconds will be lost. Consider if this loss is acceptable or if you need to round/truncate.

SELECT TO_TIMESTAMP('2023-10-27 10:00:00', 'YYYY-MM-DD HH24:MI:SS') FROM dual;
SELECT TO_DATE(SYSTIMESTAMP) FROM dual; -- Implicitly truncates fractional seconds

3

When dealing with time zones, ensure you are using the correct casting functions (`TO_TIMESTAMP_TZ`, `FROM_TZ`) and that the source data has a valid time zone if applicable.

SELECT FROM_TZ(CAST(SYSTIMESTAMP AS TIMESTAMP), 'America/New_York') FROM dual;
SELECT TO_TIMESTAMP_TZ('2023-10-27 10:00:00 -05:00', 'YYYY-MM-DD HH24:MI:SS TZH:TZM') FROM dual;

4

If the error occurs during an implicit conversion in a `WHERE` clause or `SELECT` list, explicitly cast one or both sides of the comparison or expression to ensure compatibility.

SELECT * FROM your_table WHERE CAST(your_timestamp_column AS DATE) = TO_DATE('2023-10-27', 'YYYY-MM-DD');

2. Validate and Standardize Input Data Formats medium

Ensure the string literal or column used for casting adheres to a recognized format.

1

Examine the source data that is being cast. If it's a string literal, verify its format against the expected format mask in your `TO_DATE` or `TO_TIMESTAMP` function.

2

If the source data is from a column, check its actual values and data type. There might be unexpected characters or formats that prevent successful casting. Use `DUMP` or `HEX_DUMP` to inspect raw data if necessary.

SELECT DUMP(your_string_column) FROM your_table WHERE ROWNUM = 1;

3

If the input string format is inconsistent, you may need to pre-process the data to standardize it before attempting the cast. This could involve using `REPLACE` or regular expressions.

SELECT TO_TIMESTAMP(REPLACE(your_malformed_string_column, '-', '/'), 'YYYY/MM/DD HH24:MI:SS') FROM your_table;

4

Ensure that the format mask provided to `TO_DATE` or `TO_TIMESTAMP` precisely matches the input string's structure. Pay attention to separators (e.g., '-', '/', '.'), time components (HH24, MI, SS), and fractional seconds (FF).

SELECT TO_TIMESTAMP('27/10/2023 10:00:00.123', 'DD/MM/YYYY HH24:MI:SS.FF3') FROM dual;

3. Handle `NULL` Values Gracefully easy

Prevent errors by explicitly handling `NULL` values before attempting datetime casting.

1

Identify if the `NULL` values in the source datetime column or string literal are causing the ORA-30077 error. While `NULL`s usually propagate, certain implicit conversions might behave unexpectedly.

2

Use the `NVL` or `COALESCE` function to provide a default value when the source is `NULL`. This default value should be compatible with the target datetime type or a string that can be successfully cast.

SELECT NVL(TO_TIMESTAMP(your_string_column, 'YYYY-MM-DD'), TO_TIMESTAMP('1900-01-01', 'YYYY-MM-DD')) FROM your_table;
SELECT COALESCE(CAST(your_date_column AS TIMESTAMP), SYSTIMESTAMP) FROM your_table;

3

Alternatively, use a `CASE` statement to explicitly check for `NULL` before performing the cast.

SELECT CASE WHEN your_string_column IS NULL THEN TO_TIMESTAMP('1900-01-01', 'YYYY-MM-DD') ELSE TO_TIMESTAMP(your_string_column, 'YYYY-MM-DD') END FROM your_table;

Oracle ORA-30077: Datetime Casting Failure