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40 lines
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1.3 KiB
Markdown
40 lines
No EOL
1.3 KiB
Markdown
# Postgres Expressions
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In addition to the expressions listed in the [Ash expressions guide](https://hexdocs.pm/ash/expressions.html), AshPostgres provides the following expressions
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## Fragments
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`fragment` allows you to embed raw sql into the query. Use question marks to interpolate values from the outer expression.
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For example:
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```elixir
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Ash.Query.filter(User, fragment("? IS NOT NULL", first_name))
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```
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# Like and ILike
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These wrap the postgres builtin like and ilike operators.
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Please be aware, these match *patterns* not raw text. Use `contains/1` if you want to match text without supporting patterns, i.e `%` and `_` have semantic meaning!
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For example:
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```elixir
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Ash.Query.filter(User, like(name, "%obo%")) # name contains obo anywhere in the string, case sensitively
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```
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```elixir
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Ash.Query.filter(User, ilike(name, "%ObO%")) # name contains ObO anywhere in the string, case insensitively
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```
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# Trigram similarity
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To use this expression, you must have the `pg_trgm` extension in your repos `installed_extensions` list.
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This calls the `similarity` function from that extension. See more https://www.postgresql.org/docs/current/pgtrgm.htmlhere: https://www.postgresql.org/docs/current/pgtrgm.html
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For example:
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```elixir
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Ash.Query.filter(User, trigram_similarity(first_name, "fred") > 0.8)
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``` |