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Description

The ORA-00920 error signifies an issue with the relational operator used within a SQL query's search condition. This error arises when the operator is either invalid or entirely missing, preventing the database from properly evaluating the condition.

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Error Message

ORA-00920: invalid relational operator

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Known Causes

4 known causes

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Missing Operator

A search condition lacks a relational operator, making it impossible for Oracle to compare values. ⚠

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Invalid Operator Used

An operator not recognized by Oracle (e.g., incorrect syntax or a typo) is employed within the WHERE clause. ⚠

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Incorrect Operator Placement

The relational operator is placed in an invalid location within the search condition, disrupting the expected syntax. ⚠

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Reserved Word Misuse

A reserved keyword is mistakenly used as a relational operator, leading to parsing errors. ⚠

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Solutions

4 solutions available

1. Correct Typographical Errors in Operators easy

Review the SQL statement for misspelled or incorrect relational operators.

1

Carefully examine the SQL query where the error occurs. Look for any character combinations that are intended to be relational operators but are not standard SQL.

2

Common incorrect operators to watch out for include typos like `=>` instead of `>=`, `=>` instead of `<=`, `><` instead of `!=` or `<>`, or using invalid characters.

SELECT * FROM employees WHERE salary => 50000; -- Incorrect
SELECT * FROM employees WHERE salary >= 50000; -- Correct

3

Replace any invalid operator with the correct SQL syntax. The standard relational operators are: `=`, `!=` (or `<>`), `>`, `<`, `>=`, `<=`. For string comparisons, `LIKE`, `NOT LIKE` are used.

SELECT * FROM products WHERE price < 100 AND category LIKE 'Electronics%'; -- Correct

2. Verify Operator Usage with Data Types medium

Ensure the relational operator is appropriate for the data types being compared.

1

Identify the columns or expressions involved in the comparison that is causing the ORA-00920 error. Determine their data types.

2

Check if the relational operator used is compatible with the identified data types. For example, you cannot directly use `=` to compare a CLOB or BLOB with a string literal without appropriate functions.

SELECT * FROM documents WHERE document_content = 'some text'; -- Potentially incorrect if document_content is CLOB/BLOB
SELECT * FROM documents WHERE SUBSTR(document_content, 1, 100) = 'some text'; -- Example of handling CLOB/BLOB

3

If comparing dates, ensure they are in a format that Oracle can implicitly or explicitly convert. Use `TO_DATE` for explicit conversion if needed.

SELECT * FROM orders WHERE order_date > '2023-01-01'; -- May fail depending on NLS settings
SELECT * FROM orders WHERE order_date > TO_DATE('2023-01-01', 'YYYY-MM-DD'); -- Correct

4

For numerical comparisons, ensure both sides of the operator are numerical or can be implicitly converted to numerical types. Avoid comparing numbers with strings that cannot be converted.

SELECT * FROM items WHERE quantity > '50'; -- May work if Oracle can convert '50' to a number
SELECT * FROM items WHERE quantity > 50; -- Preferred and safer

3. Review Subqueries and Function Calls medium

Examine the syntax of subqueries and function calls used in comparison clauses.

1

If the relational operator is part of a subquery or a function call's return value, scrutinize the syntax of that subquery or function.

2

Ensure that subqueries return a single value (scalar subquery) when used in a comparison with a single value. If a subquery returns multiple rows, you might need to use operators like `IN`, `ANY`, or `ALL`.

SELECT * FROM employees WHERE department_id = (SELECT department_id FROM departments WHERE department_name = 'Sales'); -- Correct scalar subquery
SELECT * FROM employees WHERE department_id IN (SELECT department_id FROM departments WHERE location_id = 10); -- Correct for multiple rows

3

Verify that any custom or built-in functions used in the comparison are correctly invoked and return a value compatible with the operator.

SELECT * FROM users WHERE UPPER(username) = 'ADMIN'; -- Correct function usage
SELECT * FROM users WHERE GET_USER_STATUS(user_id) = 'ACTIVE'; -- Assuming GET_USER_STATUS is a valid function

4

Pay close attention to parentheses, commas, and keywords within the subquery or function call, as misplaced elements can lead to syntax errors, including invalid operators.

4. Analyze Complex Expressions and CASE Statements advanced

Deconstruct complex expressions or CASE statements for operator errors.

1

If the error occurs within a complex expression or a `CASE` statement used in a comparison, break down the expression into smaller, manageable parts.

2

Evaluate each part of the expression or each `WHEN` clause in the `CASE` statement individually to pinpoint the exact location of the invalid operator.

SELECT
  CASE
    WHEN salary * 1.1 > 60000 THEN 'High Earner'
    WHEN salary * 1.05 <= 50000 THEN 'Low Earner'
    ELSE 'Mid Earner'
  END AS salary_category
FROM employees;
-- If ORA-00920 occurs, check each condition (salary * 1.1 > 60000, salary * 1.05 <= 50000) for operator issues.

3

Ensure that the logical operators (`AND`, `OR`, `NOT`) and relational operators within these complex structures are correctly placed and syntactically valid.

SELECT * FROM orders WHERE (order_date > SYSDATE - 30 AND total_amount < 1000) OR customer_id = 123; -- Correct use of AND/OR

4

In `CASE` statements, verify that the `THEN` part of each `WHEN` clause is correctly formatted and that the `ELSE` clause (if present) is also valid. The comparison in the `WHEN` clause is where ORA-00920 typically manifests.

SELECT
  CASE
    WHEN status = 'Completed' THEN 'Done'
    WHEN status = 'Pending' THEN 'Waiting'
    ELSE 'Unknown'
  END AS order_status_desc
FROM orders;

Oracle ORA-00920: Invalid Operator