How to open .SQLite files
I would suggest using R and the package RSQLite
SQL
What is the difference between JOIN and UNION?
UNION puts lines from queries after each other, while JOIN makes a cartesian product and subsets it — completely different operations. Trivial example of UNION: similary trivial example of JOIN:
MySQL “WITH” clause
I’m trying to use MySQL to create a view with the “WITH” clause But it doesn’t seem like MySQL supports this. I thought this was pretty standard and I’m sure Oracle supports this. Is there anyway to force MySQL to use the “WITH” clause? I’ve tried it with the MyISAM and innoDB engine. Both of … Read more
Difference between one-to-many and many-to-one relationship
Yes, it a vice versa. It depends on which side of the relationship the entity is present on. For example, if one department can employ for several employees then, department to employee is a one to many relationship (1 department employs many employees), while employee to department relationship is many to one (many employees work … Read more
Best way to do nested case statement logic in SQL Server
You could try some sort of COALESCE trick, eg: SELECT COALESCE( CASE WHEN condition1 THEN calculation1 ELSE NULL END, CASE WHEN condition2 THEN calculation2 ELSE NULL END, etc… )
Compare dates in MySQL
You can try below query,
ORA-12560: TNS:protocol adaptor error
o to the windows machine that hosts the Oracle database server Go to Start -> Run -> Services.msc in Windows. Locate OracleService < SID > (here OracleServiceORCL) and click on Start to start the oracle database service (if not already running) Once it is up and running, from the command prompt run the following:tnsping < tnsalias > (tnsalias entry you can … Read more
Difference between JOIN and INNER JOIN
They are functionally equivalent, but INNER JOIN can be a bit clearer to read, especially if the query has other join types (i.e. LEFT or RIGHT or CROSS) included in it.
SQL Server FOR EACH Loop
SQL is primarily a set-orientated language – it’s generally a bad idea to use a loop in it. In this case, a similar result could be achieved using a recursive CTE: