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transformations:merge [2017/01/01 15:32] dmitrytransformations:merge [2018/04/30 09:44] dmitry
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 This transformation appends one or more columns from another table where certain columns in both tables match. This transformation appends one or more columns from another table where certain columns in both tables match.
  
-There are two possible merge modes:+There are three possible merge modes:
  
   * Lookup Mode -- get **first** matching combination from the other table. If there are other combinations they are ignored.   * Lookup Mode -- get **first** matching combination from the other table. If there are other combinations they are ignored.
   * Left Join Mode -- get **all** matching combinations from the other table. It can increase number or rows in the current table.   * Left Join Mode -- get **all** matching combinations from the other table. It can increase number or rows in the current table.
- +  * Full Join Mode -- include all combinations of keys from both tables. Equivalent to the full outer join in SQL.
-To make full outer join, first, append rows that exist in the other table but are missing in the current table using [[transformations:keepdifferent|Keep Different]] and [[transformations:append|Append Table]] transformations and then Merge (in Left Join mode).+
  
 EXAMPLE EXAMPLE
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 | Yangtze  |  6300  |  Asia  |  East China Sea  | | Yangtze  |  6300  |  Asia  |  East China Sea  |
 | Mississippi  |  6275  |  North America  |  Gulf of Mexico  | | Mississippi  |  6275  |  North America  |  Gulf of Mexico  |
 +
 +=== Limitations ===
 +The resulting table after Merge can't have more than 134,217,728 rows. 
  
 === See also === === See also ===
   * [[transformations:append|Append another table]]   * [[transformations:append|Append another table]]
  
transformations/merge.txt · Last modified: 2023/10/11 20:49 by craigt

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