TDAJoinType
Overview
TDAJoinType specifies relations between tables.
Location
- Unit: uDACore.pas
| Value | Description |
|---|---|
| jtCross | Produces rows which combine each row from the first table with each row from the second table.<br/>SELECT * FROM table1, table2<br/> |
| jtFullOuter | Combines the effect of applying both left and right outer joins. Where records in the FULL OUTER JOINed tables do not match, the result set will have NULL values for every column of the table that lacks a matching row.<br/>SELECT * FROM table1 FULL OUTER JOIN table2 ON table1.ID = table2.ID<br/> |
| jtInner | Creates a new result table by combining column values of two tables (A and B) based upon the join-predicate. The query compares each row of A with each row of B to find all pairs of rows which satisfy the join-predicate. When the join-predicate is satisfied, column values for each matched pair of rows of A and B are combined into a result row. <br/>SELECT * FROM table1 INNER JOIN table2 ON table1.ID = table2.ID<br/> |
| jtLeftOuter | Returns all the values from an inner join plus all values in the left table that do not match to the right table.<br/>SELECT * FROM table1 LEFT OUTER JOIN table2 ON table1.ID = table2.ID<br/> |
| jtRightOuter | Returns all the values from the right table and matched values from the left table (NULL in case of no matching join predicate)<br/>SELECT * FROM table1 RIGHT OUTER JOIN table2 ON table1.ID = table2.ID<br/> |