Operators Oracle
Arithmetic operators
Arithmetic operators mainly +, -, *, /, which are binary operators, its use requires two operands to be operated.
Join operator
In oracle, with the double pipe connection string (||) represents
--将工资大于1000$的员工的姓名和工资拼接输出
SELECT ename||'is a'||job FROM emp WHERE salary>1000;
Comparison Operators
-
Relational operators primarily by size comparison operation using the relationship
Equal =
<Less than
<= Less than or equal
> Greater than
> = Greater than or equal
Does not mean:
! =, ^ =, <>, = Not XXX yyy, Not (XXX = yyy)
Empty judgment
It is null if the operand is NULL returns TRUE
is not null
Fuzzy query
like fuzzy string comparison
not like
boolean operation
AND two conditions must be met
OR as long as one of the two conditions
NOT negated
Wildcards
In the where clause, can use wildcards with conditions like
% (Percent sign): used to represent any number of characters, or may have no character.
_ (Underscore): Indicates the exact unknown character.
? (Question mark): used to indicate the exact unknown character.
# (Pound sign): used to indicate the exact Arabic numerals, 0-9.
[AZ] (brackets): it is used to represent a range of characters, in this case from a to z.
SQL operator precedence
An arithmetic operator
Connector 2
3 Comparison operators
4 IS[NOT]NULL, LIKE, [NOT]IN
5 [NOT] BETWEEN
6 NOT
7 AND
8 OR
Suitable location
Where conditions are for comparison:
equal: =, <, <=,>,> =, <>
comprising: IN, NOT IN EXISTS, NOT EXISTS
range: BETWEEN ... AND, NOT BETWEEN ... AND
fuzzy matching: LIKE, NOT LIKE
verification null values: IS NULL, IS NOT NULL
Boolean operators: AND, OR, NOT
While studying records, if any deficiencies welcome message pointing ...
