oracle 操作符

--- oracle 操作符

-- 1. 算术运算符（oracle算术运算符包括 +、-、*、/）

-- 2. 关系运算符

---- <1> 等于 ( = )

---- <2> 不等于 ( != 、< >  )

---- <3> 小于 ( < )

---- <4> 大于（ > ）

---- <5> 大于或者等于 ( > = )

---- <6> 小于或者等于 ( < = )

-- 3.逻辑运算符

---- <1> and

---- <2> or

---- <3> not                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            -- 4.字符串连接符  ( || )

------在oracle中，字符串连接符用||，

SELECT * from base_dept;

SELECT * from zhonghq_dept;

SELECT (ID||'aa'||dept_name) AS dept_name FROM base_dept WHERE dept_code IS NOT NULL;