多项选择题
A.You want to create a nonequijoin.
B.The tables to be joined have multiple NULL columns.
C.The tables to be joined have columns of the same name and different data types.
D.The tables to be joined have columns with the same name and compatible data types.
E.You want to use a NATURAL join, but you want to restrict the number of columns in the join condition.
多项选择题 Which two tasks can you perform using only the TO_CHAR function? （）
单项选择题 Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE You issue these statements: CREATE table new_emp ( employee_id NUMBER, name VARCHAR2(30)); INSERT INTO new_emp SELECT employee_id , last_name from employees; Savepoint s1; UPDATE new_emp set name = UPPER(name); Savepoint s2; Delete from new_emp; Rollback to s2; Delete from new_emp where employee_id =180; UPDATE new_emp set name = James; Rollback to s2; UPDATE new_emp set name = James WHERE employee_id =180; Rollback; At the end of this transaction, what is true?（）
多项选择题 Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER NOT NULL, Primary Key EMP_NAME VARCHAR2(30) JOB_ID NUMBER SAL NUMBER MGR_ID NUMBER References EMPLOYEE_ID column DEPARTMENT_ID NUMBER Foreign key to DEPARTMENT_ID column of the DEPARTMENTS table You created a sequence called EMP_ID_SEQ in order to populate sequential values for the EMPLOYEE_ID column of the EMPLOYEES table. Which two statements regarding the EMP_ID_SEQ sequence are true? （）