Database Operations (iv), scalar functions

Scalar functions

1, Uppercase: Upper ();

Select upper (column name) from table name;

2, lowercase: lower ();

Select lower (column name) from table name;

3, intercept the string: substring ();

Select substring (column name, from whom to start, intercept a few) from the table name;

4, the starting position of the specified string: charindex ();

Select CHARINDEX (' Value 1 ', column name, starting from a few) from table name;

' Value 1 ': Who to list: where to look

Select CHARINDEX (column name 1, column name 2, intercept several) from table name;

Compared to two columns

It can also be written in the Where condition to make its statement meaningful: SELECT * from table name where CHARINDEX (column name 1, column name 2, intercept several) >0;

5. Print length, go to the trailing space Len ();

Select Len (column name) from table name;

6, remove the left blank print value, LTrim ();

Select LTrim (column name) from table name;

Remove the right blank print value, RTrim ();

Select RTrim (column name) from table name;

7. Start capturing values from the leftmost column: Left ();

Select Left (column name, intercept several) from table name;

Intercept values from the rightmost of the column: Right ();

Select Right (column name, intercept several) from table name;

8, empty value: IsNull ();

Select IsNull (column name, ' xx ') from table name;

Note: If xx is empty, print empty

　　　　　　　

　　　　　　　　

Database Operations (iv), scalar functions