35610302 Teradata Joins Types

March 16, 2018 | Author: Pratik Lakhpatwala | Category: Data Management, Information Retrieval, Computer Programming, Areas Of Computer Science, Sql


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Description

Join Methods: Icon Join Step Description Correlated A correlated version of the Exclusion Merge Join. A sub-query Exclusion Merge is "correlated" when it references columns of outer tables in the join enclosing (outer) query. Correlated Exclusion Product join A correlated version of the Exclusion Product Join. A sub-query is "correlated" when it references columns of outer tables in the enclosing (outer) query. Correlated Inclusion Merge join Correlated Inclusion Product join Dynamic Hash join A correlated version of the Inclusion Merge Join. A sub-query is "correlated" when it references columns of outer tables in the enclosing (outer) query. A correlated version of Inclusion Product Join. A sub-query is "correlated" when it references columns of outer tables in the enclosing (outer) query. An equality join between a small table and a large table on non-primary index columns without placing the large table into a spool file. For Dynamic Hash join to be used, the left table must be small enough to fit in a single partition. Exclusion Merge A merge join where only the rows that do not satisfy (are NOT join IN) any condition specified in the request are joined. Exclusion Product join A Product Join where only the rows that do not satisfy (are NOT IN) any condition specified in the request are joined. Exists join A join which returns all the left table rows that satisfy a condition, if the right table is non-empty. Full Outer Merge join A join in which full outer joins of two or more tables perform an inner join of those tables according to a join condition and, in addition, return rows from the both the tables, which were not returned in the result of the inner join, extending these rows with null values. A join in which full outer joins of two or more tables perform an inner join of those tables according to a join condition and, in addition, return rows from the both the tables, which were not returned in the result of the inner join, extending these rows with null values. A hash join. Full Outer Product join Hash join A join which returns all the left table rows that do not satisfy a condition. Intersect join A join in which the INTERSECT ALL clause is used. which were not returned in the result of the inner join. Left Outer Merge join A join in which left outer joins of two or more tables perform an inner join of those tables according to a join condition. including the duplicate values. In addition. based on the row hash of the columns involved. A join in which left outer joins of two or more tables perform an inner join of those tables according to a join condition. The conditions may also match some column of that single row to the primary or secondary index of the second table. Returns the rows that are present only in the left and not in the right table including duplicate values. which were not returned in the result of the inner join. Left Outer Product join Minus/Except join Nested join A join in which a WHERE condition specifies a constant value for a unique index of one table. rows are returned from the 'left' join table. Inclusion Merge join A join in which only the rows that satisfy (are IN) any condition specified in the request are joined. extending these rows with null values. In addition. rows are returned from the 'right' join table. Inner Merge join A join which retrieves rows from two tables. Inner Product join A join of two tables. extending these rows with null values.Hash Star join A join in which two or more small relations are joined to large a relation. extending these rows with null values. Inclusion Product join A join in which only the rows that satisfy (are IN) any condition specified in the request are joined. . where the rows returned are common to both tables. then puts them onto a common AMP. A join which occurs when the MINUS ALL clause is used. Not Exists Join join Right Outer Merge join A join in which right outer joins of two or more tables perform an inner join of those tables according to a join condition. which were not returned in the result of the inner join. if the right table has no rows. In addition. return rows from the 'left' join table. the condition in the query must match another column of the first table to a NUSI or USI of the second table. Second. First. Row ID join . and a nested join is done between the two tables to retrieve the row IDs from the second table. In addition. extending these rows with null values. rows are returned from the 'right' join table.Right Outer Product join A join in which right outer joins of two or more tables perform an inner join of those tables according to a join condition. only a subset of the NUSI or USI values from the second table are qualified via the join condition. A join that requires two conditions. which were not returned in the result of the inner join.
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