Check out example codes for "how to create index mysql". It will help you in understanding the concepts better.

Code Example 1

create index your_index_name on your_table_name(your_column_name) using HASH;
or
create index your_index_name on your_table_name(your_column_name) using BTREE;

Code Example 2

# index_name will identify your index for future reference
CREATE INDEX index_name ON table_name (column_name);

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