Common Criteria for SQL statement judgment

Conditional judgment notation:

when performing actions on a daily record, judge the conditions that are restricted-----

operator :

= <> (mismatch check) ! = < > <= >=

Example: Products not produced by supplier 1003 Where vend_id<>1003

and two both meet

OR Two conditions in which one can be satisfied

Note: You should pay attention to the priority of both and and or when using And>or

For example: List all products priced at more than $10 and manufactured by 1002 or 1003?

Where vend_id=1002 or vend_id=1003 and prod_price>=10; This error

Where (vend_id=1002 or vend_id=1003) and prod_price>=10;

between and 　　

Prices for all products between $5 and $10

WHERE Prod_price between 5 and 10;

Like '%_ City% '

Percent percent (% )--any character, any number of occurrences,

Can be used anywhere in search mode, or multiple wildcard characters can be used

For example: Any word that begins with jet where prod_name like ' jet% ';

Underline (_)--match only a single character

Where prod_name like ' _ton anvil ';

In () within the range

Not in () out of range

Is null empty

Common Criteria for SQL statement judgment