SQL – Using the Set Operators Set operators are used to join the results of two (or more) SELECT statements.The SET operators available in Oracle 11g are UNION,UNION ALL,INTERSECT,and MINUS. The UNION set operator returns the combined results of the two SELECT statements.Essentially,it removes duplicates from the results i.e. only one row will be listed […]
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SQL – The SQL SELECT Statement Retrieving data using the SQL Select Statement SQL is a comprehensive database language. SQL, pronounced Sequel or simply S-Q-L, is a computer programming language used for querying relational databases following a nonprocedural approach. When you extract information from a database using SQL, this is termed querying the database. A […]
SQL – Subqueries to Solve Queries A subquery is best defined as a query within a query. Subqueries enable you to write queries that select data rows for criteria that are actually developed while the query is executing at run time. More formally, it is the use of a SELECT statement inside one of the […]