Analysis of MySQL string functions

1. left function, used to intercept the string content of the query field. select left (content, 50) as summary from article; here, it means to query only the first 50 characters of the content column. Here, Chinese characters are also considered as only one character.

2. The right function is the opposite of the left function. It intercepts the content from the back.

3. The upper function processes lowercase letters in the queried content in uppercase. Select upper (title) as title from article;

4. The lower function is the opposite of the upper function. It performs lower-case processing.

5. Use the substr function to crop a string at a specified position. This function is more flexible than left and right. Select substr (content, 10, 50) from article. 50 characters are truncated starting from 10th characters (the first character is 1 and not 0). select substr (content, 10) from article, starting from 10th characters to the end; select substr (content,-20) from article, intercepting 20 characters from the end.