Then we get the following results for the various To put this together, assume we have tables t1: Name to be present will cause the join to combine Relations since only the listed columns areĬonsiderably more risky since any schema changes toĮither relation that cause a new matching column Reasonably safe from column changes in the joined Of all column names that appear in both input tables.Īppear only once in the output table. Order), followed by any remaining columns from T2, JOIN USING produces one output columnįor each of the listed column pairs (in the listed ON produces all columns from T1 followed by all columns from Need to print both of the matched columns, since they USING suppresses redundant columns: there is no (a, b) produces the join condition ON T1.a = ![]() It takes aĬomma-separated list of the shared column names andįorms a join condition that includes an equalityĬomparison for each one. Specific situation where both sides of the join use the Shorthand that allows you to take advantage of the Value expression of the same kind as is used in aįrom T1 and T2 match if the ON expression evaluates to true. General kind of join condition: it takes a Boolean Null values in the columns of T1 is added. Also,įor each row of T2 that does not satisfy the joinĬondition with any row in T1, a joined row with FULL OUTER JOINĪdded with null values in columns of T2. Will always have a row for each row in T2. The converse of a left join: the result table ![]() The joined table always has at least one row forĮach row in T2 that does not satisfy the joinĬondition with any row in T1, a joined row isĪdded with null values in columns of T1. Then, forĮach row in T1 that does not satisfy the joinĬondition with any row in T2, a joined row isĪdded with null values in columns of T2. Row for each row in T2 that satisfies the joinįirst, an inner join is performed. However writing * might be useful to emphasize that additionalįor each row R1 of T1, the joined table has a Since that behavior is the default (unless you have changed theĬonfiguration option). Table name to explicitly specify that descendant tables are However, the reference produces only the columns thatĪppear in the named table - any columns added in subtables are Of not only that table but all of its descendant tables, unless Table inheritance hierarchy, the table reference produces rows When a table reference names a table that is the parent of a The result of the FROM list is an intermediate virtual table thatĬan then be subject to transformations by the WHERE, GROUP BY, and If more than one table reference isĪre cross-joined (that is, the Cartesian product of their rows Schema-qualified), or a derived table such as a subquery, aĬombinations of these. ![]() In a comma-separated table reference list.įROM table_reference ]Ī table reference can be a table name (possibly Clause derives a table from one or more other tables given
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