Can we compare NULL in Oracle?

Can we compare NULL in Oracle?

Nulls with Comparison Conditions Because null represents a lack of data, a null cannot be equal or unequal to any value or to another null. However, Oracle considers two nulls to be equal when evaluating a DECODE function.

How can I compare two dates in Oracle?

The correct way to do the date comparison is: WHERE ORDER_DATE = TO_DATE(’07-JUN-2000′,’DD-MON-YYYY’,’NLS_DATE_LANGUAGE=ENGLISH’); It will use the index on the ORDER_DATE column, so it will much better in terms of performance. Also, it is comparing dates and not strings.

Can you compare NULL values?

A comparison to NULL is never true or false. Since NULL can never be equal to any value, it can never be unequal, either.

Is NULL and NULL in Oracle?

SQL Reference for Oracle NoSQL Database The IS NULL operator tests whether the result of its input expression is NULL. If the result of the input expression is empty, IS NULL returns false. Otherwise, IS NULL returns true if and only if the single item computed by the input expression is NULL.

What two functions can be used to replace NULLs before aggregating?

MIN(), MAX() set functions, these also eliminate NULLs before returning a result.

Can we subtract two dates in Oracle?

Answer: Oracle supports date arithmetic and you can make expressions like “date1 – date2” using date subtraction to get the difference between the two dates.

IS NULL is equal to 0?

The answer to that is rather simple: a NULL means that there is no value, we’re looking at a blank/empty cell, and 0 means the value itself is 0.

Where NULL is NULL?

Fabian Pascal on SQL NULLs A scalar expression on a table without rows evaluates incorrectly to NULL, instead of 0. The expression “NULL = NULL” evaluates to NULL, but is actually invalid in SQL; yet ORDER BY treats NULLs as equal (whatever they precede or follow “regular” values is left to DBMS vendor).

Is null or empty in Oracle?

Answer: An empty string is treated as a null value in Oracle.

How do I compare a date against Null in SQL?

A comparison of a date against null will result in nothing being returned by the main query – which is technically the correct response. If you don’t want that then you would need to substitute a string value for the null using the NVL function.

Is select to_date null a valid SQL statement?

select to_date (null, ‘mm/dd/yyyy’) from dual is a perfectly valid SQL statement that returns NULL. The error you are getting strongly implies that at least some of the rows in the start_date column are not actually strings in the format you expect or that map to invalid dates (i.e. the string ’13/35/2007′).

Why does to_date return null when starting a date?

Basically to_date is exploding and throwing an error when camp.start_date is not a valid date. If start_date is NULL, no exception is thrown. is a perfectly valid SQL statement that returns NULL.

Is it safe to compare string with date?

Never ever compare a STRINGwith DATE. You might just be lucky, however, you force Oracle to do an implicit data type conversionbased on your locale-specific NLS settings. You must avoid it.

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