select from two tables sql without join

Tags: style blog c http a widthFor SQL joins, learning may be a bit confusing. We know that the join syntax for SQL has a lot of inner, outer, left, and sometimes it's not very clear what the result set looks like for a select. There is an article on Coding horror that explains the

. The Inner join combines the records in these tables only if there is a matching value on the public field of the two tables.The ability to use INNER JOIN for departments and Employees tables to select all employees in each department. Instead, you can create an outer

, table2 the name of the table to which the record is to be combined. Field1,field2 The name of the field to join. If they are not numbers, these fields must have the same data type and contain homogeneous data, but they do not have to have the same name. COMPOPRany relational comparison operator: "=", "DescriptionYou can use the INNER JOIN operation in any FROM clause. This is the most common type of

columns in the category table Program codeSelect. *, B. *, c. * from (ctarticle a left join ctclass B on. classid = B. classid) left join ctnclass c on. nclassid = c. nclassid // Function. Sometimes, an article table contains data that is not present in an individual category table. You can use this syntax to read all the data in the article table.// A is the document table, B is the main category, and c i

Label:Left join returns records that include all the records in the left table and the equivalent of the junction fields in the right tableRight join returns records that include all records in the right table and the junction fields in the left tableINNER JOIN (equivalent join) returns only rows that have the same

the public field of the two tables.You can use INNER JOIN for departments and Employees tables to select all employees in each department. Instead, you can create an outer join by using a LEFT JOIN or right JOIN operation to

tables.You can use INNER JOIN for departments and Employees tables to select all employees in each department. Instead, you can create an outer join by using a LEFT JOIN or right JOIN operation to

Tags: left joins right join INNER JOINLeft join returns records that include all the records in the left table and the equivalent of the junction fields in the right tableRight join returns records that include all records in the right table and the junction fields in the left tableINNER JOIN (equivalent

20060324012 a20050112 2 20060324023 a20050113 3 20060324034 a20050114 4 2006032404NULL NULL 8 2006032408(The number of rows affected is 5 rows) result Description: Look closely, you will find that the result of the left join is exactly the opposite, this time is based on the right table (B), a table is not sufficient place with null padding. --------------------------------------------3.inner Join

Tags: case ble add left join Karl Baidu Oss intersection useUsing the Join table, the defect is inner join, the left join used in development and the right join belong to outer join,outer join