CODEWITHSUNDEEP
pythonmysql
Steven Yong
Steven Yong

Reputation: 5436

What do %% and % in these queries mean?

I have the following 2 Python codes:

def direct_by_node(self, node, partition_size):
    return '''select req.id, req.profile_id as profile
                  from table1 attr
                  where id % {0} = {1}'''.format(partition_size, node)

and then

def find_by_node(self, node, partition_size):
    return '''select req.id, req.profile_id as profile
                  from table1 attr
                  where id %% {0} = {1}'''.format(partition_size, node)

I am wondering what % and %% in the 2 MySQL queries are about?

Edit:

When I try %% in MySQL Workbench, looks like I have a syntax error, looks like %% is invalid.

Upvotes: 1

Views: 81

Answers (1)

mahyard
mahyard

Reputation: 1238

The first one is a Modulo operation and calculates the remainder of id divided by partition_size then compare it with node.

Look at a simple example here:

mysql> SELECT 253 % 7;
    -> 1 # because 253 = 36*7 + 1

More function_mod examples

As you noticed %% is not a valid operator.

Upvotes: 1

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