Use of like in SQL statements

Like statements have a crucial role in SQL Structured Query language.
The syntax format for the LIKE statement is: SELECT From table name where field name like corresponding value (substring), it is mainly for the character field, its function is to retrieve the string containing the corresponding substring in a character field column.
Suppose there is a database with a table table1, there are two fields in Table1, respectively, name and sex are all character data. Now we're going to look at the records that begin with the word "Zhang" in the Name field, with the following statement:
SelectFrom table1 where name like "Zhang "
If you want to query for records that end with "Zhang", the statement is as follows:
SelectFrom table1 where name is like " Zhang "
This uses the wildcard character ", it can be said that the like statement is inseparable from the wildcard character. Let's take a look at the wildcard character in detail below.
Match type
Mode
Examples and representative values
Description
Multiple characters
CC stands for CC,CBC,CBC,CABDFEC, etc.
It is the same as a wildcard character in a DOS command that represents multiple characters.

Multiple characters%
%c% represents AGDCAGD, etc.
This method is used in many programs, mainly the query contains substrings.

special characters []
a[]a represents aa
Replace

Single character?
B?b represents BRB,BFB, etc.
Same as in DOS command? Wildcards, which represent a single character

Single number #
K#k Representative k1k,k8k,k0k
In general, the difference is that the generation can only represent a single number.

Character Range

• [A-z] represents any of the 26 letters of A to Z in any one of the ranges specified in a range
  Continue on
  Exclude [! character] [!a-z] represents 9,0,%,*, etc. it represents only a single character
  Number exclusion [! number] [!0-9] for a,b,c,d, etc. ibid.
  Combination type character [range type] character cc[!a-d] #代表ccF # etc can be combined with several other ways
  Suppose the following records are in table table1:
  Name Sex
  Zhang Xiaoming Male
  Lee Tomorrow Man
  Lee A-day female
  Wang 55 Male
  King Qingyue Five Male

Let's take a look at the following example:
Example 1, the Query Name field contains the word "Ming".
Select from table1 where name like '%% '
Example 2, the Query Name field begins with the word "Li".
Select from table1 where name like ' Lee '
Example 3, the Query Name field contains a number.
Select from table1 where name like '%[0-9]% '
Example 4, the Query name field contains lowercase letters.
Select from table1 where name like '%[a-z]% '
Example 5, the Query Name field does not contain a number.
Select from table1 where name like '%[!0-9]% '

The above example can list what values to be obvious. But here we highlight the difference between a wildcard "" and a "%".
Many friends ask, why do I use "%" instead of "" When I have a different representation of all characters in the above query?
Let's take a look at the following example to see what happens:
Select from table1 where name
Select from table1 where name as%%
As you can see, the previous statement lists all the records, and the next record lists the records that contain "Ming" in the Name field, so it's best to use "%" instead of "" when we make a query with a substring in the character field. Only at the beginning or only at the end, and not at both ends by "*" in place of any character.

Use of like in SQL statements