SELECT distance FROM Direct_distance AS T1 JOIN Student AS T2 ON T1.city1_code  =  T2.city_code JOIN Student AS T3 ON T1.city2_code  =  T3.city_code WHERE T2.Fname  =  "Linda" AND T2.Lname  =  "Smith" AND T3.Fname  =  "Tracy" AND T3.Lname  =  "Kim"
How far do Linda (first name) Smith (last name) and Tracy (first name) Kim (last name) live?
create table Student (
        StuID        INTEGER PRIMARY KEY,
        LName        VARCHAR(12),
        Fname        VARCHAR(12),
        Age      INTEGER,
        Sex      VARCHAR(1),
        Major        INTEGER,
        Advisor      INTEGER,
        city_code    VARCHAR(3),
        FOREIGN KEY(city_code) REFERENCES City(city_code)
 );
create table Direct_distance (
  city1_code varchar(3) ,
  city2_code varchar(3) ,
  distance INTEGER,
  FOREIGN KEY(city1_code) REFERENCES City(city_code),
  FOREIGN KEY(city2_code) REFERENCES City(city_code)
  
) ;
create table City (
       city_code  	VARCHAR(3) PRIMARY KEY,
       city_name  	VARCHAR(25),
       state		VARCHAR(2),
       country		VARCHAR(25),
       latitude		FLOAT,
       longitude	FLOAT
);
INSERT into Student values ( 1001, 'Smith', 'Linda', 18, 'F', 600, 1121,'BAL');
INSERT into Direct_distance values ( 'BAL' , 'ATL' , 576 ) ;
INSERT into City values ( 'BAL' , 'Baltimore' , 'MD' , 'USA' , 39.288 , -76.617 ) ;
INSERT INTO Student VALUES [(1001, 'Smith', 'Linda', 18, 'F', 600, 1121, 'BAL'), (1002, 'Kim', 'Tracy', 19, 'F', 600, 7712, 'HKG')]
INSERT INTO Direct_distance VALUES [('BAL', 'ATL', 576), ('BAL', 'BAL', 0)]
INSERT INTO City VALUES [('BAL', 'Baltimore', 'MD', 'USA', 39.288, -76.617), ('PIT', 'Pittsburgh', 'PA', 'USA', 40.437, -80.0)]