MySQL – Should you put an index on a Boolean field to help query performance?
I am often asked if it makes sense to place an index on a Boolean field in order to improve query performance. In general, because a boolean value can only…
Read moreMySQL Removing duplicate rows – Part II
Using ALTER IGNORE TABLE [TABLENAME] ADD UNIQUE INDEX `UNIQUE_INDEX` ([FIELDNAME]) to remove duplicate rows in a table is a fast an efficient process, however on large tables where the physical…
Read moreMySQL Master and Slave have different Query Execution Plans
I recently ran into a situation where a Delete across a large time period was taking an extensive amount of time to run when replicated to the Slave, although the…
Read moreMySQL How to delete duplicate records and rows of data
The fastest and easiest way to delete duplicate records is my issuing a very simple command. alter ignore table [tablename] add unique index `unique_index` ([fieldname]) What this does is create…
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