CSE :: Database System 2 - CS
- There is an equivalent join expression that can be substituted for all subquery expressions.
- Each index consumes extra storage space and also requires overhead maintenance time whenever indexed data change value.
- The HAVING clause acts like a WHERE clause, but it identifies groups that meet a criterion, rather than rows.
- The qualifier DISTINCT must be used in an SQL statement when we want to eliminate duplicate rows.
- DISTINCT and its counterpart, ALL, can be used more than once in a SELECT statement.
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