CODEWITHSUNDEEP
mysqlsql
xjshiya
xjshiya

Reputation: 925

MySQL bug in where clause?

I have a query which has typographical error:

SELECT 
     SUM(qty) 
AS 
    'aqty1' 
FROM 
     po_details 
WHERE 
     product_id ='1196' 
AND 
     so_number = '1m';

It should be:

SELECT 
     SUM(qty) 
AS 
     'aqty1' 
FROM 
     po_details 
WHERE 
     product_id ='1196' 
AND 
     so_number = '1';

But the first wrong query which have so_number = '1m' mysteriously outputs correctly, the same output as the second correct query does, which should not be the case, right?

product_id and so_number's data types are both INT. so_number = '1m' should've worked if so_number's data type is VARCHAR, since I've enclosed the 1m inside quotes, and the condition set was so_number LIKE '%1m%'.

So why is the above typo query works? Shouldn't MySQL error and says that it can't find the 1m and consider it as 1? Is this a known bug? I am using MySQL 5.6.14.

Here's a screenshot:

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Upvotes: 0

Views: 223

Answers (1)

Darshan Mehta
Darshan Mehta

Reputation: 30849

It's implicit conversion, performed by MySQL. You can read about that here:

When an operator is used with operands of different types, type conversion occurs to make the operands compatible. Some conversions occur implicitly.

e.g.:

mysql> SELECT 1+'1';
        -> 2
mysql> SELECT CONCAT(2,' test');
        -> '2 test'

Upvotes: 3

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