MySQL update with and operator

Chaitanya Bankanhal :

I had written some wrong syntax for an SQL query. But still, it outputted no error with a java tomcat server. Running on Debian 9. MySQL Version:

mysql  Ver 14.14 Distrib 5.7.24, for Linux (x86_64)

The query was as follows, I had misplaced the comma ',' with 'and' after the set operator

UPDATE table_pod_print set print_status = 1 and operator_id = 2091 where id = 1

I tried running it on the console, which gave me the following output:

ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction

Please help me in understanding why the query worked in the first place.

Karol Dowbecki :

In MySQL SELECT 1 AND 0; produces 0 because the AND operator evaluates operands as a logical AND. Looking at your query the SET print_status was evaluated as (adding additional brackets for clarity):

print_status = (1 AND (operator_id = 2091)) 

which mean it would be 1 AND 1 if operator_id = 2091 for updated id = 1 row was true and 1 AND 0 if not.