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I am having trouble with a mysql query. I want to exclude values of 2. So I thought I would do following:
table products id | name | backorder ------------------- 1 | product1 | NULL 2 | product2 | NULL 3 | product3 | 2 SELECT name from `products` p WHERE backorder <> '2' However, This is not giving the desired result of product1, product 2 It is giving an empty results table.
On the other hand if I use
SELECT name from `products` p WHERE backorder = '2' Then it produces: product3. But I want to get those records where it is not equal to 2.
Something is not working with the <> '2'. Could it be that the NULL values are throwing it off? Can anyone suggest a fix.
Thanks in advance!
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<> is Standard SQL-92; != is its equivalent. Both evaluate for values, which NULL is not -- NULL is a placeholder to say there is the absence of a value.
By default, a column can hold NULL values. The NOT NULL constraint enforces a column to NOT accept NULL values. This enforces a field to always contain a value, which means that you cannot insert a new record, or update a record without adding a value to this field.
MySQLi For Beginners The symbol <> in MySQL is same as not equal to operator (!=). Both gives the result in boolean or tinyint(1). If the condition becomes true, then the result will be 1 otherwise 0.
use IS NULL or IS NOT NULL to compare NULL values because they are simply unknown.
SELECT name from products p WHERE backorder IS NULL OR backorder <> 2 SQLFiddle Demo (added some records)
Working with NULL Values
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