subquery example

External dependencies by sub-query: Independent subquery, correlated subquery By comparison operator differences: In,exists,any,some,all and many other forms Third: Use of sub-query: First create two tables (Student table and teacher table) # create student table MySQL > CREATE Table Tb_student (-stu_id Long, class varchar (5), score int); Query OK, 0 rows affected (0.23 sec) # Creating

Problem:Find out the names, jobs, and salaries of employees with lower wages in the EMP table than any salesperson ("salesman").Analysis:Salespeople have a lot of records in the EMP table, everyone's salary is not equal, if the return "than any employee's salary is lower" condition, return than "maximum wage is lower" can be.If you do it with a subquery, multiple records are returned in the subquery. Runnin

[Mysql] An example of subquery bitsCN.com [Mysql] An example of subquery Assume that the table my_tbl contains three fields a, B, and c. now we need to query the minimum value of column B under each different value of column a in the table. For example, the table re

This example describes the MySQL subquery usage. Share to everyone for your reference, specific as follows: Suppose the table my_tbl contains three field a,b,c; now you need to query the number of records for which column B is the minimum for each different value of column A in the table. For example, the table record is: A b C1 3 ' CD '2 3 ' nHD '1 5 ' BG '2

[Mysql] An example of subquery assumes that the table my_tbl contains three fields a, B, and c; now we need to query the minimum value of Column B under each different value of column a in the table. For example, the table record is: a B c1 3 'cd' 2 3 'nhd' 1 5 'bg '2 6 'cd' 1 7'kiy' 3 7'bf'3 8'ndf' expected results is: a B c1 3 'cd' 2 3 'nhd '3 7' _ (1) One of t

1. Use subquery In the create table statement By using subqueries In the create table statement, you can insert data in the table while creating a new table. SQL> Create Table dept1 (deptno, dname, Loc) as select deptno, dname, LOC from Dept; if it is to create all columns, you can use * to simplify the statement. SQL> Create Table emp1 as select * from EMP; 2. Use the subquery SQL in the update Statement>

mapply.mid = Mconfig.mid WHERE Mapply.aid In ( SELECT Aid From ' mapply ' where state = $state ORDER BY ' atime ', ' uid ' DESC ) So no error, MO away thought OK, but after running found that the data have problems and simply read out the content of the application form is not the same, only to find limit position misplaced, and then put limit in, the results of the following error This version of the MySQL doesn ' t yet support ' LIMIT in/all/any/some

Assume that the table my_tbl contains three fields A, B, and C. Now we need to query the minimum value of Column B under each different value of column A in the table. For example, the table record is: A B C 1 3 'cd' 2 3 'nhd' 1 5 'bg' 2 6 'cds' 1 7 'kiy' 3 7 'Password' 3 8 'ndf' Expected result: A B C 1 3 'cd' 2 3 'nhd' 3 7 'Password' (1) One method is to first find the minimum value of B under each a value, an

Label:Problem:Check out the employee's name, job, and salary, which are higher than the salary of all sales staff.Analysis:Any can represent arbitrary, but this problem requires a higher salary than all salespeople, then use a different keyword all.All is used with the relational operator to represent comparisons with all elements in a subquery.Code Demo: All subqueries /Code parsing:>all: Larger than all values in the subquery result, that is, lar

" cellspacing = "0" cellpadding = "0"> Select *From (select ename, salFrom emp ); 7 multi-row subquery Multi-row subquery can only use the multi-row comparison operator (in any all) -- For example, you can use either of the following methods to query the employee information of a department whose name is * (not) SALES or ACCOUNTING. -

Subquery 1 (subquery in WHERE), where in subquerySubquery A subquery is a compilation of complex queries by embedding several small queries with different functions in a complete query statement, to help readers better understand the concept of subqueries. Subquery return resultsData types that can be returned by subqu

", "Conttesdfsdee", 5, 1);INSERT into article values (8, "Fff8", "Conttesdfsdfee", 77, 1);Example: Select Article_id,article_title,article_content from article where article_comments in (select Max (article_comments) From article group by articlecategory_id);4.from Sub-queryDefinition: The From subquery is the result of a query (a table in memory) that is treated as a temporary table and then processed.From

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