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Is associated with the explain analysis, connection customer_source_id this table query, type for eq_ref, is normal, as shown in figure:
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But in the query customer_type_id associated with this form, the type is ALL, as shown in figure:
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If only the query lc_customer_type primary key, can normal use index, as shown in figure:
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What reason is this? Is lc_customer this table has a problem or lc_customer_type has a problem?
CodePudding user response:
The left and the right connections, understand later knew why, give priority to with a queryCodePudding user response:
Under the understanding about the connection