在Oracle中，有一个教师表teacher的结构如下： ID NUMBER(5) NAME VARCHAR2(25) EMAIL VARCHAR2(50) 下面哪个语句显示没有 Email地址的教师姓名：A、SELECT name FROM teacher WHERE email = NULLB、SELECT name FROM teacher WHERE email NULLC、SELECT name FROM teacher WHERE email IS NULLD、SELECT name FROM teacher WHERE email IS NOT NULL-易过题库-题库最全的搜题网站

在Oracle中，有一个教师表teacher的结构如下： ID NUMBER(5) NAME VARCHAR2(25) EMAIL VARCHAR2(50) 下面哪个语句显示没有 Email地址的教师姓名：

ASELECT name FROM teacher WHERE email = NULL

BSELECT name FROM teacher WHERE email NULL

CSELECT name FROM teacher WHERE email IS NULL

DSELECT name FROM teacher WHERE email IS NOT NULL

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