DB2 can implement a join in three ways using a merge join, a nested join or a hybrid join. Explain the differences?

2852

What is dclgen (declaration generator)?

1059

Can one database have multiple instances?

1054

what is utility for parm lib

2377

How do I add a column to an existing table in db2?

1032

Outputs of explain are with matchcols = 0. What does this signify?

1060

i want to maintain uniqueness on pdf without make lf??????????

2158

What is a plan and package in db2?

1104

What is database alias db2?

1127

What is cursor in dbms?

1068

SET is the ANSI standard for variable assignment, SELECT is not. SET can only assign one variable at a time, SELECT can make multiple assignments at once. If assigning from a query, SET can only assign a scalar value. If the query returns multiple values/rows then SET will raise an error. SELECT will assign one of the values to the variable and hide the fact that multiple values were returned (so you'd likely never know why something was going wrong elsewhere - have fun troubleshooting that one) When assigning from a query if there is no value returned then SET will assign NULL, where SELECT will not make the assignment at all (so the variable will not be changed from it's previous value) As far as speed differences - there are no direct differences between SET and SELECT. However SELECT's ability to make multiple assignments in one shot does give it a slight speed advantage over SET.

2671

On which levels locks can be applied?

1133

What is runstats and reorg in db2?

1304

What is innodb buffer pool?

1054

How do I optimize a query in db2?

1101