Modern Database Management 11th Edition by Jeffrey A. HofferUse th.pdf
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The document discusses using the UNION statement in SQL to combine lists of care center names and locations with laboratory names and locations. It outlines the syntax for the UNION operator, emphasizing the option to include duplicate values using the 'ALL' keyword. An example query is provided to illustrate how to select and rename fields from two different tables, 'care_center_t' and 'laboratory_t'.
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Modern Database Management 11th Edition by Jeffrey A. HofferUse th.pdf
- 1. Modern Database Management 11th Edition by Jeffrey A. Hoffer Use the UNION statement to provide a combined listing of care center names and their locations as well as laboratories and their location. The list should be sorted by location, in ascending order. (You should use aliases to rename the fields in this query.) Please provide results! Solution The UNION operator is used to combine the result-set of two or more SELECT statements.The UNION operator selects only distinct values by default. To allow duplicate values, use the ALL keyword with UNION. Syntax: SELECT column_name(s) FROM table1 UNION ALL SELECT column_name(s) FROM table2; Now Let us consider that there are two tables namely care_center_t and laboratory_t where the care_center_t contains rows like care_center name ,location1 and the laboratory_t consists of rows such as laboratories and Locations2. SELECT operator is used in selecting of particular rows from the table. So, now we select rows namely care_center_name and location1 from care_center_t table and Loboratories and location2 from laboratory_t table. The Database Query for the above problem is SELECT care_center_name as name,location1 as location from care_center_t UNION all Select laboratory as name ,location2 as location from laboratory_t