how to subquery in sql

IamlasongRequirements: The contents of the table need to be changed, the content of the change is placed in a temporary table, and the SQL statement is used to update multiple fields in the formal table.If you update a field directly with the field name = subquery, multiple fields are updated, and the fields are written in parentheses, as follows:Update TB_JG TSet t.jgfl = ' SD ',(T.zj_code, T.ZJ_MC) = (sel

the course table, where two tables have COURSE.CNO=SCORE.CNO connections -- use a table with more data to query the main table, where score is the main table Second, aggregate function 1, Max,min: Take maximum value, minimum value --inquire about the car with the lowest fuel consumption SELECT * FROM car where oil= (select max (oil) from car) 2, Avg: Averaging --Check the average price of the car Where as is used to alias 3, Count: Take the total number --Find out how many cars there are. i

--subquery Exercises/*1, sub-query (internal query) before the main query (outer query) one execution completes 2, the result of the subquery is used by the main query 3, in the query list using subqueries, can only be a single-row single-column. See Exercise 2 4, do not use the ORDER BY statement in a subquery unless you are doing top N analysis, the efficiency

tree, B-tree, C + tree, b* tree | 2013-09-21 12:30:18 || 1379 | MySQL basic SQL statements Common Management SQL | 2013-09-21 12:39:23 |+------+----------------------------------------------------------------+---------------------+7 rows in Set (0.01 sec) To sort query results:Order by Field_name {asc| DESC}As follows: The code is as follows Copy Code Mysql> Select Id

employee information is the same as that of the 141 job type. The salary is higher than that of the 143 job. SQL> conn hr/123456Connected.SQL> select last_name, job_id, salary2 FROM employees3 WHERE job_id =4 (SELECT job_id5 FROM employees6 WHERE employee_id = 141 ); Eg: query the employee information with the lowest salary Select last_name, job_id, salaryFROM employeesWHERE salary =(Select min (salary)FR

; = ANY) Example 10,Query the salaries of each department manager. -- Query the salary of each department MANAGER. SELECT * FROM emp WHERE sal = ANY (select min (sal) FROM emp WHERE job = 'manager' group by deptno ); Example 11,The result shows that the salary of each department is higher than that of the manager. -- SELECT * FROM emp WHERE sal> ANY (select min (sal) FROM emp WHERE job = 'manager' group by deptno) for the salaries of each Department greater than the MANAGER ); Example 12,The res

Label:One, the basic type of sub -Query multiple rows subquery (1) Use the in operator for multi-line subqueries. (Summary: Multiple rows of subqueries available after the in operator) For example: Query the highest-paid employee information for each position. Sql>select ename, Job, Sal from EMP where sal in (select Max (SAL) from EMP Group by Job);--Single row subqu