[MySQL] Filtering data

Tag: greater than or equal to MYSQ search validation order by database where SEL nbsp

Specifying search criteria using the WHERE clause of the SELECT statement

In the SELECT statement, the data is filtered according to the search criteria specified in the WHERE clause, given after the table name

SELECT column name 1, column name 2 from table name WHERE condition;

Condition is a specific value of the data in the column

WHERE clause position

SELECT + from + WHERE + ORDER by

WHERE clause operator

Operator description

= equals

<> Not equal to

! = does not equal

< less than

<= less than or equal to

> Greater than

>= greater than or equal to

Between between the specified two values

Check individual values

SELECT column name 1, column name 2 from table name WHERE column name 1 operator (<,;, =) column data;

　　

Mismatch check

SELECT column name 1, column name 2 from table name where column name 1 <> column value;

Range value Check

SELECT column name 1, column name 2 from table name WHERE column Name 1 between value 1 and value 2;

Null value Check

SELECT column name from table name WHERE column name is NULL;

　　

Null and mismatched when you select a column that does not have a specific value by filtering, you may want to return a row that has a null value. However, no, because the unknown has a special meaning, the database does not know whether they match, so they are not returned when matching filtering or mismatched filtering.

Therefore, when filtering data, be sure to verify that the returned data does give a row with NULL in the filtered column.

[MySQL] Filtering data