What is the main difference between a UNION statement and a UNION ALL statement? 1. A UNION statement eliminates duplicate rows; a UNION ALL statement includes duplicate rows. 2. A UNION statement can be used to combine any number of queries; a UNION ALL statement can be used to combine a maximum of two queries. 3. A UNION statement can only combine queries that have parallel fields in the SELECT list; a UNION ALL statement can combine queries with differing SELECT list structures. 4. A UNION statement cannot be used with aggregate functions; a UNION ALL statement can be used with aggregate functions. 5. There is no difference between the two statements; they are interchangeable.2 6594
1 SELECT a.field1, b.field2, c.field3, d.field4 2 FROM atable a, atable b, ctable c, dtable d 3 ? 4 ORDER BY 1 What is the minimum number of joins that must be specified on line 3 in the sample code above to properly link the tables? Notice that the table "atable" is aliased twice: once as "a" and once as "b." 1. One join 2. Two joins 3. Three joins 4. Four joins 5. Five joins6 5898
SELECT flavor, SUM (ice_cream_sales) FROM sales_detail GROUP BY flavor ORDER BY 2 DESC If the "sales_detail" table contains ten records with different values in the flavor column (two "vanilla," three "chocolate," four "strawberry," and one NULL), how many rows are returned by the sample code above? 1. 0 rows 2. 1 row 3. 3 rows 4. 4 rows 5. 10 rows8 7088
Which one of the following is a reason that an INSERT statement might cause an error instead of executing correctly? 1. The INSERT statement was attempting to insert a record into a view that was created from more than one table. 2. The INSERT statement was attempting to insert a record using a combination of constants and values from an existing table. 3. The INSERT statement was attempting to insert a record with a non-NULL value into a table that has that column defined as NULL. 4. The INSERT statement was attempting to insert a record into a table by selecting a record from that same table. 5. The INSERT statement was attempting to insert a record into a view rather than a table.1 4959
How to retrieve a second highest salary from a table? Note:Suppose salaries are in duplicate values eg: Name Sal Malli 60000 Pandi 60000 Rudra 45000 Ravi 450008 9796
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