MySql query - If table two tables have same data, select from more important table

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I have three tables

rules, default_client_rules and client_rules

Rules contains a list of all the rules, their names, parameters etc.

default_client_rules has a list of rules that applies to all users. Table:

`id`, `rule_id`, `num_required`

The user can also create their own rules stored in client_rules.

`id`, `rule_id, `num_required`

The user can create their own rules that would override the default rules so in my tables I might have:

default_client_rules 21, 3, 0

client_rules 7, 3, 1

The client rules takes precedence over the default client rules table. I want to write a query to display all rules. The bit I'm having trouble with is, in the scenario above when there is an entry in client_rules for the same rule as in default_client_rules I only want to select the client_rules entry.

asked 53 secs ago

Peck3277

371

MySql query - If table two tables have same data, select from more important table