Very often we need to extract last 1 month, 2 months data from mysql DB. Here we will show easy way to get the data of given interval. SELECT * from testtable WHERE startdate BETWEEN DATE_SUB(NOW(), INTERVAL 1 MONTH) AND DATE_SUB(NOW(), INTERVAL 2 MONTH) The above query will return records whose order date is between one and … Read more
Easiest way to do this is to add a UNIQUE index on the column. When you write the ALTER statement, include the IGNORE keyword. Like so: ALTER IGNORE TABLE jobs ADD UNIQUE INDEX idx_name (site_id, title, company); This will drop all the duplicate rows. As an added benefit, future INSERTs that are duplicates will error … Read more
Some of the optimizations performed by MySQL on where clauses as follow: Removal of unnecessary parentheses: ((a AND b) AND c OR (((a AND b) AND (c AND d)))) To (a AND b AND c) OR (a AND b AND c AND d) Constant folding: (a<b AND b=c) AND a=5 To b>5 AND b=c AND … Read more