database processing function

In the database, the basic common aggregate functions sum, max, min, avg, count are used the most, in addition to other functions that are used more are as follows (SQL case insensitive):

1.ASCII(): Process the ASCII value of the first letter of the returned field in the query statement

2.UPPER() / LOWER(): Process query statement return field case

3.TO_CHAR () / TO_DATE(): string conversion, date conversion

5.REVERSE(): reverse the string

6.REPLACE(): replace specific characters

 

select replace(name, 'a', 'A'), RTRIM(name), LTRIM(name), LOWER(name), name from table where rownum<6;