Hash connections hash and merge connections are used to separate internal and external sources. The connection condition cannot be used as a search parameter. If you do not specify search parameters for a table or an inappropriate index, scan the table. It is possible to hash and merge connections with bookmarked search operations, but not necessarily, unless the connection type is specified forcibly. The following query explicitly declares a hash connection. Each table in the Join Operation specifies a search condition, and both tables have clustered indexes or overwrite indexes. SELECTm. ID, n. ValueFROMM2C
Hash connection
Hash and merge connections are used to separate internal and external sources. The connection condition cannot be used as a search parameter. If you do not specify search parameters for a table or an inappropriate index, scan the table. It is possible to hash and merge connections with bookmarked search operations, but not necessarily, unless the connection type is specified forcibly.
The following query explicitly declares a hash connection. Each table in the Join Operation specifies a search condition, and both tables have clustered indexes or overwrite indexes.
SELECT m. ID, n. Value
FROM M2C m inner hash join M2D n ON n. ID = m. ID
WHERE m. GroupID = @ Group1 AND n. GroupID = @ Group2
-The execution plan in "19" consists of three parts: index search operations on each source plus hash connections. The cost details of hash connections are shown in-20.
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