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mysql advanced query 2
Select advanced query has the following syntaxes, fuzzy query like, sub query, record set union.
Fuzzy query like has the following three symbols %, _, []. The syntax is as follows:
% represents any number, any character. E.g:
SELECT * FROM shaicheng WHERE username LIKE '%里%';
SELECT * FROM shaicheng WHERE username LIKE '%里';
_ represents any single character. The syntax is as follows:
SELECT * FROM SHAICHENG WHERE GROUPNAME LIKE '_士';
SELECT * FROM SHAICHENG WHERE changci LIKE '__场';
[AB] One character is optional.
The subquery syntax is as follows:
If there are two joined tables,
If you are a relational operator, the result of the subquery can only be one (single row and single column). If you want to do multi-line value judgment, there is in. The in syntax is as follows:
The record set union syntax is as follows:
The queried column names are displayed according to the column names of the first table. The empty query syntax is as follows:
Sorts and conditions can be written on the last query statement:
