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shantanu88d
Starting Member
35 Posts |
 Posted - 2011-06-18 : 11:29:51
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I was asked which one of these queries would run faster...select * from emp where emp_name like 'John%' andselect * from emp where emp_name like '%John' I answered that second would run slower.Then I was asked what to do to make it run faster ???Any ideas folks ?There are no failures...only experiences! |
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robvolk
Most Valuable Yak
15732 Posts |
Posted - 2011-06-18 : 11:36:36
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| The first search term can use an index on the emp_name table, since it does not begin with a wildcard character.The 2nd term cannot be optimized that way, unless you modify the table and the term as below:ALTER TABLE emp ADD rev_emp_name AS REVERSE(emp_name)CREATE INDEX ix_rev_emp_name ON emp(rev_emp_name)SELECT * FROM emp_name WHERE rev_emp_name LIKE REVERSE('%John') |
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speed issue in like operators ?