Answer Posted / prakash.matte
If we have table 'temp' with columns: id(primary key),
field1, field2, field3, to remove the duplicate (field1,
field2, field3) data we can use either of the below queries
1. delete t1.* from temp t1, temp t2
where t1.id>t2.id and t1.field1=t2.field1 and
t1.field2=t2.field2 and t1.field3=t2.field3;
2. alter ignore table temp ADD UNIQUE INDEX
duprows(field1,field2,field3);
> here we can remove the duprows index by using the
following query:
alter table temp drop index duprows;
we can apply index on the columns as we don't require the
duplicate data, so we don't need to execute the query to
delete the index
Is This Answer Correct ? | 1 Yes | 0 No |
Post New Answer View All Answers
What is the use of header() function in php?
How to convert a character to an ascii value?
Tell me what are the correct and the most two common way to start and finish a php block of code?
What is the basic syntax of Php?
Do you know how can php and html interact?
How does csrf token work?
Explain me soundex() and metaphone()?
What is the main difference between php 4 and php 5?
How to merge values of two arrays into a single array?
What is strstr php?
What is dao in php?
How send email using php?
Tell me what's the difference between include and require?
Can we override static method?
Tell me what is the main difference between require() and require_once()?