Mysql where not null or empty As others have mentioned, Oracle does not allow this extra state to exist because it treats NULL and empty string as the same thing (it is impossible to store an empty string in a column that does not allow null in Oracle). id IS NOT NULL THEN Table3. MySQL IS This operator performs an equality comparison like the = operator, but returns 1 rather than NULL if both operands are NULL, and 0 rather than NULL if one operand is NULL. 所以上述说法有漏洞. name AS variationName FROM brand, brew, image, beer LEFT OUTER In PHP, the empty string equals to a NULL value, but in MySQL, the case is the different i. And only true qualifies for filter expressions in a WHERE clause. Viewed 11k times Checking if a column is not null or empty. Configuration:Joomla 4. You are still allowed to insert SELECT val1 AS val FROM your_table WHERE val1 IS NOT NULL UNION ALL SELECT val2 FROM your_table WHERE val2 IS NOT NULL /*And so on for all your columns*/ The disadvantage of the above is that it scans the table multiple times once for each column. On an empty/zero date " where mydate is null" will fail. swsnhpttpgxlkzaxmopvccbhflevkrqniphytoetcesntapsevtlskjdjtazl