SQL Search Statements and filter statements

First of all, recommend a more useful database management software: Navicat Premium.

• The most important retrieval function in a database: SELECT statement

1. Retrieve a single column: Select Column name from table name;

2. Retrieve multiple columns: Select Column Name 1, column name 2,...from table name;

3. Retrieve all Columns: SELECT * from table name;

4. Retrieve different rows: Select DISTINCT column name from table name; */* Column with duplicate values, show only different values

5. Search Limit number of rows: Select Column name from table name limit quantity;/* Returns data with no more than a few rows

6. Retrieves the specified number of rows: Select Column name from table name limit (m,n);/* returns n rows beginning with line m

7. Use fully qualified table name: Select Table name. column name from database. Table name;

• Sort statement: ORDER BY statement

1, order BY column name 1, column name 2;

2. Order BY column name Dec; descending order

• Filter statement: where statement

1. WHERE clause operator:

Column name =; column name <>; column name <; column name >; Column name >=; column name <=; column name between and; column name is null;

2. Combine WHERE clause:

①and operator: Select column Name 1, column name 2, column name 3 from table name where column name 1= and column Name 2 =;

②or operator:

③in Operator: Specifies the condition range, where column name in (M,n,... ）;

④not operator: Specified range, not in (M,n,...);

3, the use of like+ wildcard filter: Wildcard characters used to match the value of a part of the special character, wildcard characters need to use single quotation marks.

①%: Any number of occurrences of any character;

②% character%: Identifies a value that matches any position that contains a character;

③x%y: Indicates that there is more data with the beginning of x ending with y;

④ underline: matches a single character;

4. Regular expressions

SQL Search Statements and filter statements