Concept explainers
DISTINCTROW Keyword:
The “DISTINCTROW” keyword omits data based entire duplicate records, not like just duplicate fields. The syntax for “DISTINCT” keyword is as follows:
Syntax:
SELECT DISTINCTROWcol_Name FROM table_Name1 INNER JOIN table_Name2 ON table_Name1.col_Name = table_Name2.col_Name ORDER BY table_Name1;
GROUP BY Clause:
The GROUPBY clause is used to group the result of a SELECT statement done on a table where the tuple values are similar for more than one column
Syntax:
SELECT expression1, expression2, expression_n, aggregate_function(expression)FROM table_name WHERE conditions GROUP BY expression1, expression2, expression_n;
SUM function:
The “SUM” function is used to add the value and then return the sum of the expression in a “SELECT” statement.
Syntax:
SELECT SUM (exp) FROM table_Name [WHERE condition];
INNER JOIN keyword:
“INNER JOIN” keyword is used to select all the matching records of both the table.
Syntax:
SELECT col_Name FROM table_Name1 INNER JOIN table_Name2 ON table_Name1.col_Name = table_Name2.col_Name;
Want to see the full answer?
Check out a sample textbook solutionChapter 7 Solutions
EBK DATABASE SYSTEMS: DESIGN, IMPLEMENT
- Delete the OWNER_INDEX 3 index from the OWNER table.arrow_forwardProblems 25 and 26 are based on the following query: SELECT P_CODE, P_DESCRIPT, P_QOH, P_PRICE, V_CODE FROM PRODUCT WHERE V_CODE = '21344' ORDER BY P_CODE; How should you rewrite the query to ensure that it uses the index you created in your solution to Problem 25?arrow_forwardEnsure that the only legal values for the BDRMS column in the CONDO_UNIT table are 1, 2, or 3.arrow_forward
- Subject: DatabaseWrite the SQL statements for following modification tasks: a) Add constraint to the table BORROWER named borrower_cardno_pk to create the attribute name as the primary key. b) Delete the column city from the table BORROWER c) Modify the column of "phone" in table BORROWER, change the data type into type of VARCHAR2 with length of 20.arrow_forwardWrite a query which set the following constraints in Customers table (in MySQL). First Name and city must be entered. Last name must be different of each customer.arrow_forwardselect * from cast where cast_id=162652763; Use explain to display the query plan without creating any index. Now create an index to speed up the query. Use explain and timer to show the improvement.arrow_forward
- Write and execute a SQL query to list all patient numbers and encounter ids which do not have any data (missing rows) in VisitSummary table. Order the result by patient number, encounter id. Write and execute a SQL query to list all patients whose information about race or gender has changed during their future visits. A future visit is defined as T1.encounter_id < T2.encounter_id. Your output should have patient number, old and new race values, old and new gender values, and the encounter ids. Write and execute a SQL query to list all the patient data for all encounters. Even if patient data is missing in other tables, you still need to list the patient_nbr and encounter_id in your output. Your output should list all the columns (without repeating them) starting with encounter_id, patient_nbr... and it should be ordered by patient_nbr and then encounter_id. Write and execute a SQL query to list all the patient data for all encounters. If the patient data is missing…arrow_forwarda. Write a query to get all unique first names that start with the letter W from the student table. Output the names in all upper case. Sort the results in ascending order. Write a query to get the first 3 characters of all last names that start with an T from the student table and sort them in descending order.arrow_forwardProblem 104 Write a query to display the patron ID and the average number of days that patron keeps books during a checkout. Limit the results to only patrons who have at least three checkouts. Sort the results in descending order by the average days the book is kept, and then in ascending order by patron ID (Figure P7.104). SELECT P.PAT_ID, AVG(DATEDIFF(C.CHECK_IN_DATE,C.CHECK_OUT_DATE) ) AS "AVERAGE DATE KEPT" FROM PATRON P JOIN CHECKOUT C ON P.PAT_ID=C.PAT_ID GROUP BY P.PAT_ID HAVING COUNT(C.CHECK_OUT_DATE) >= 3 Order by "AVERAGE DAYS KEPT" DESC,P.PAT_ID ASC; With the query below I am getting the wrong headers were returned, some expected rows were missing and some unexpected rows were returned. How can i correct this query to ge the expected results? Thanksarrow_forward
- 10. When we find out that there are some miss spellings in the query?arrow_forwardThis is the problem: (from Database Systems Book, 13th ed) Write a query to display the author last name, first name, book title, and replacement cost for each book. Sort the results by book number and then author ID (Figure P7.92). (25 rows)arrow_forwardin pl/sql ,use Cursor to get all the records from table job_history for employee_id 121arrow_forward
- Database Systems: Design, Implementation, & Manag...Computer ScienceISBN:9781305627482Author:Carlos Coronel, Steven MorrisPublisher:Cengage LearningProgramming with Microsoft Visual Basic 2017Computer ScienceISBN:9781337102124Author:Diane ZakPublisher:Cengage LearningDatabase Systems: Design, Implementation, & Manag...Computer ScienceISBN:9781285196145Author:Steven, Steven Morris, Carlos Coronel, Carlos, Coronel, Carlos; Morris, Carlos Coronel and Steven Morris, Carlos Coronel; Steven Morris, Steven Morris; Carlos CoronelPublisher:Cengage Learning
- A Guide to SQLComputer ScienceISBN:9781111527273Author:Philip J. PrattPublisher:Course Technology Ptr