What are the limits of table and column in SQL?
As shown here: http://msdn.microsoft.com/en-us/library/ms143432.aspx
MS SQL Server can contain 2,147,483,647 objects. Objects include tables, views, stored procedures, UDFs, triggers, rules, defaults, constraints, etc. In short, you are unlikely to run out of space for objects.
1,024 columns for narrow tables, 30,000 for wide tables.
If you're talking about a different database platform then I'm sure Google will help.
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This will be different from the database, but I can tell you that if you are thinking about anything close to the maximum number of columns in a table, you need to reconfigure. You have an absolute limit on bytes per write, and while you can create columns that together would add to more bytes than this write would allow in some databases (I know SQL Server will allow you to do this), you eventually will have to redisgn, because one entry cannot fit the limit. If you plan to have many null columns in each record, you will need the corresponding tables instead. Smaller tables also tend to perform better and are much easier to maintain.
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SQL as a language does not require such restrictions and assumes an unlimited number of columns, tables, and something-you. In addition, SQL, as a language, considers all operations to be constant and instantaneous in time.
As other responders have pointed out, different RDBMSs implement things very differently from each other. And few people implement SQL completely.
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