Merge pull request #147 from behrman/relational-data-typos

Fix typos - relational-data.Rmd
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Hadley Wickham 2016-07-13 20:22:56 -04:00 committed by GitHub
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1 changed files with 2 additions and 2 deletions

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@ -235,7 +235,7 @@ Graphically, that looks like:
knitr::include_graphics("diagrams/join-outer.png")
```
The most commonly used join is the left join: you use this whenever you lookup additional data out of another table, because it preserves the original observations even when there isn't a match. The left join should be your default join: use it unless you have a strong reason to prefer one of the others.
The most commonly used join is the left join: you use this whenever you look up additional data out of another table, because it preserves the original observations even when there isn't a match. The left join should be your default join: use it unless you have a strong reason to prefer one of the others.
Another way to depict the different types of joins is with a Venn diagram:
@ -383,7 +383,7 @@ dplyr | SQL
Note that "INNER" and "OUTER" are optional, and often omitted.
Joining different variables between the tables, e.g. `inner_join(x, y, by = c("a" = "b"))` uses a slightly different syntax in SQL: `SELECT * FROM x INNER JOIN y ON x.a = y.b`. As this syntax suggests SQL supports a wide range of join types than dplyr because you can connect the tables using constraints other than equality (sometimes called non-equijoins).
Joining different variables between the tables, e.g. `inner_join(x, y, by = c("a" = "b"))` uses a slightly different syntax in SQL: `SELECT * FROM x INNER JOIN y ON x.a = y.b`. As this syntax suggests SQL supports a wider range of join types than dplyr because you can connect the tables using constraints other than equality (sometimes called non-equijoins).
## Filtering joins {#filtering-joins}