Recent questions tagged sql

Consider:$\mathrm{DEPT(dname,\ location)}$$\mathrm{STUDENT(name,\ regno,\ gpa,\ level,\ dept)}$$\mathrm{COURSE(cno,\ cname,\ dept)}$$\mathrm{TAKE(regno,\ cno)}$and the SQ...

Consider relations $\mathrm{R}$ and $\mathrm{S}$.Five SQL commands are shown:Command I :SELECT R.* FROM R WHERE EXISTS (SELECT * FROM S WHERE R.a = S.c);Command II :SELEC...

Consider:$\mathrm{Observation(Seq,\ BirdName,\ ObservationCount)}$with primary key:$\mathrm{(Seq,\ BirdName)}$The following statement inserts combinations of sequence num...

Relation $\mathrm{R1(A,B)}$ contains:$$\begin{array}{|c|c|} \hline \mathrm{A} & \mathrm{B} \\ \hline 1 & 2 \\ 2 & 2 \\ 3 & 3 \\ 4 & 3 \\ 4 & 2 \\ 4 & 1 \\ 5 & 0 \\ \hline...

Consider the relation:$$\begin{array}{|c|c|c|} \hline \mathrm{EmployeeCode} & \mathrm{Supervisor} & \mathrm{Name} \\ \hline \mathrm{S001} & \mathrm{NULL} & \mathrm{A} \\ ...

Relevant relations are:$\mathrm{BUILDING(BID,\ BName,\ Address)}$$\mathrm{IN\_BUILDING(EID,\ BID)}$Which of the following queries correctly find the names of buildings wh...

Consider relations:$\mathrm{Product}$$\mathrm{Inventory}$where the underlined attributes in the original examination are primary keys.The following query returns product ...

Consider,SELECT DISTINCT TBL1.COL1 FROM TBL1 WHERE COL1 IN (SELECT COL1 FROM TBL2);Which SQL statement produces the same result?SELECT DISTINCT TBL1.COL1 FROM TBL1 UNION ...

Consider the relation $R(a,b)$. The relation may contain duplicate tuples.Which of the following queries are guaranteed not to contain duplicate tuples, regardless of the...

Three relations with the same schema are maintained for three regions:$\mathrm{TokyoProduct}$, $\mathrm{NagoyaProduct}$, and $\mathrm{OsakaProduct}$$\mathrm{ProductNo}$ i...

The database contains relations $\mathrm{animals}$ and $\mathrm{visits}$, with $\mathrm{aid}$ identifying an animal.Which SQL query returns the names of animals that visi...

Conceptually, in which order does SQL process the following three operations?$\mathrm{WHERE}\rightarrow\mathrm{HAVING}\rightarrow\mathrm{GROUP\ BY}$ $\mathrm{WHERE}\right...

The $\mathrm{Employee}$ relation contains:$$\begin{array}{|c|c|c|c|} \hline \mathrm{EmployeeNo} & \mathrm{Name} & \mathrm{DateOfBirth} & \mathrm{Department} \\ \hline 000...

The relation is:$\mathrm{Midterm}(\mathrm{ClassName},\mathrm{SubjectName},\mathrm{StudentNo},\mathrm{Name},\mathrm{Score})$.The objective is to calculate the average scor...

The relation $\mathrm{ExamResult}$ stores examination records for the previous three years:$\mathrm{ExamResult}(\mathrm{StudentNo},\mathrm{ExamDate},\mathrm{Score},\mathr...

Relation $\mathrm{R}(\mathrm{at1},\mathrm{at2},\mathrm{at3})$ contains: $$\begin{array}{|c|c|c|} \hline \mathrm{at1} & \mathrm{at2} & \mathrm{at3} \\ \hline 12 & 15 & 510...

A concert-ticket system contains $\mathrm{Sales}$ and $\mathrm{Payment}$.Relevant rules are:a row is placed in $\mathrm{Sales}$ when a purchase application is made; if pa...

Consider the relation: $$\begin{array}{c}\mathbf{EmployeeQualification} \\[4pt]\begin{array}{|c|c|}\hline\mathrm{EmployeeCode} & \mathrm{Qualification} \\\hline\mathrm{S0...

Consider the following tables.The following SQL query is executed:SELECT AVG(TotalSales) AS AverageSales FROM Product LEFT OUTER JOIN ProductSales ON Product.ProductCode ...

Consider,$\mathrm{Users}(\mathrm{userid},\mathrm{name},\mathrm{age})$$\mathrm{Dogs}(\mathrm{dogid},\mathrm{owner},\mathrm{name},\mathrm{breed},\mathrm{age})$$\mathrm{dogi...

Let $\mathrm{R}$ and $\mathrm{S}$ be relations.For which of the following relational operations is it not necessary that $\mathrm{R}$ and $\mathrm{S}$ be union-compatible...

The database contains:$\mathrm{Users}(\mathrm{uid},\mathrm{name},\mathrm{dob},\mathrm{user\_type})$$\mathrm{Posts}(\mathrm{pid},\mathrm{folder},\mathrm{summary})$$\mathrm...

The Adjacency List table stores the data for the tree structure shown below. Which SQL keyword should be inserted at $\mathbf{[a]}$ to retrieve the leaf nodes of the tree...

Consider:SQL Statement $\mathbf{1}$$\mathrm{SELECT\ *}$ $\mathrm{FROM\ R}$ $\mathrm{UNION}$ $\mathrm{SELECT\ *}$ $\mathrm{FROM\ R}$;SQL Statement $\mathbf{2}$$\mathrm{SEL...

Consider the following $\mathrm{Product}$ table:$$\begin{array}{|c|c|c|c|} \hline \mathrm{ProductID} & \mathrm{Product} & \mathrm{SupplierID} & \mathrm{UnitPrice} \\ \hli...

Given:$\mathrm{Homes}(\mathrm{home\_id},\mathrm{city},\mathrm{bedrooms},\mathrm{bathrooms},\mathrm{area})$$\mathrm{Transactions}(\mathrm{home\_id},\mathrm{buyer\_id},\mat...

Given the relation: $$\begin{array}{|c|c|c|c|} \hline \mathrm{Sname} & \mathrm{Sid} & \mathrm{Region} & \mathrm{Quota} \\ \hline \mathrm{Frances} & 25 & \mathrm{TX} & 100...

An auditing company was hired to analyze the database of the SUS (Unified Health System). Its first task is to identify pairs of registered doctors who have the same name...

Two tables are given below : $$\begin{array}{c@{\qquad}c}\mathrm{\mathbf{Orders}} & \mathrm{\mathbf{Products}} \\[4pt]\begin{array}{|c|c|c|}\hline\mathrm{Date} & \mathrm{...

A table $\mathrm{Scores}$ stores each student's marks in Japanese and Mathematics.Let,$A$ mean the student's Japanese score is at least the Japanese average.$B$ mean the ...