# buildpg
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[](https://codecov.io/gh/samuelcolvin/buildpg)
[](https://pypi.python.org/pypi/buildpg)
[](https://github.com/samuelcolvin/buildpg)
[](https://github.com/samuelcolvin/buildpg/blob/master/LICENSE)
Query building for the postgresql prepared statements and asyncpg.
Lots of more powerful features, including full clause construction, multiple values, logic functions,
query pretty-printing and different variable substitution - below is just a very quick summary.
Please check the code and tests for examples.
## Building Queries
Simple variable substitution:
```py
from buildpg import render
render('select * from mytable where x=:foo and y=:bar', foo=123, bar='whatever')
>> 'select * from mytable where x=$1 and y=$2', [123, 'whatever']
```
Use of `V` to substitute constants:
```py
from buildpg import V, render
render('select * from mytable where :col=:foo', col=V('x'), foo=456)
>> 'select * from mytable where x=$1', [456]
```
Complex logic:
```py
from buildpg import V, funcs, render
where_logic = V('foo.bar') == 123
if spam_value:
where_logic &= V('foo.spam') <= spam_value
if exclude_cake:
where_logic &= funcs.not_(V('foo.cake').in_([1, 2, 3]))
render('select * from foo :where', where=where_logic)
>> 'select * from foo foo.bar = $1 AND foo.spam <= $2 AND not(foo.cake in $3)', [123, 123, ['x', 'y']]
```
Values usage:
```py
from buildpg import Values, render
render('insert into the_table (:values__names) values :values', values=Values(a=123, b=456, c='hello'))
>> 'insert into the_table (a, b, c) values ($1, $2, $3)', [123, 456, 'hello']
```
## With asyncpg
As a wrapper around *asyncpg*:
```py
import asyncio
from buildpg import asyncpg
async def main():
async with asyncpg.create_pool_b('postgres://postgres@localhost:5432/db') as pool:
await pool.fetchval_b('select spam from mytable where x=:foo and y=:bar', foo=123, bar='whatever')
>> 42
asyncio.run(main())
```
Both the pool and connections have `*_b` variants of all common query methods:
- `execute_b`
- `executemany_b`
- `fetch_b`
- `fetchval_b`
- `fetchrow_b`
- `cursor_b`
## Operators
| Python operator/function | SQL operator |
| ------------------------ | ------------ |
| `&` | `AND` |
| `|` | `OR` |
| `=` | `=` |
| `!=` | `!=` |
| `<` | `<` |
| `<=` | `<=` |
| `>` | `>` |
| `>=` | `>=` |
| `+` | `+` |
| `-` | `-` |
| `*` | `*` |
| `/` | `/` |
| `%` | `%` |
| `**` | `^` |
| `-` | `-` |
| `~` | `not(...)` |
| `sqrt` | `|/` |
| `abs` | `@` |
| `contains` | `@>` |
| `contained_by` | `<@` |
| `overlap` | `&&` |
| `like` | `LIKE` |
| `ilike` | `ILIKE` |
| `cat` | `||` |
| `in_` | `in` |
| `from_` | `from` |
| `at_time_zone` | `AT TIME ZONE` |
| `matches` | `@@` |
| `is_` | `is` |
| `is_not` | `is not` |
| `for_` | `for` |
| `factorial` | `!` |
| `cast` | `::` |
| `asc` | `ASC` |
| `desc` | `DESC` |
| `comma` | `,` |
| `on` | `ON` |
| `as_` | `AS` |
| `nulls_first` | `NULLS FIRST` |
| `nulls_last` | `NULLS LAST` |
Usage:
```py
from buildpg import V, S, render
def show(component):
sql, params = render(':c', c=component)
print(f'sql="{sql}" params={params}')
show(V('foobar').contains([1, 2, 3]))
#> sql="foobar @> $1" params=[[1, 2, 3]]
show(V('foobar') == 4)
#> sql="foobar = $1" params=[4]
show(~V('foobar'))
#> sql="not(foobar)" params=[]
show(S(625).sqrt())
#> sql="|/ $1" params=[625]
show(V('foo').is_not('true'))
#> sql="foo is not true" params=[]
```
## Functions
| Python function | SQL function |
| ------------------------------------------- | ------------- |
| `AND(*args)` | `<arg1> and <arg2> ...` |
| `OR(*args)` | `<arg1> or <arg2> ...` |
| `NOT(arg)` | `not(<arg>)` |
| `comma_sep(*args)` | `<arg1>, <arg2>, ...` |
| `count(expr)` | `count(expr)` |
| `any(arg)` | `any(<arg1>)` |
| `now()` | `now()` |
| `cast(v, cast_type)` | `<v>::<cast_type>` |
| `upper(string)` | `upper(<string>)` |
| `lower(string)` | `lower(<string>)` |
| `length(string)` | `length(<string>)` |
| `left(string, n)` | `left(<string>, <n>)` |
| `right(string, n)` | `right(<string>, <n>)` |
| `extract(expr)` | `extract(<expr>)` |
| `sqrt(n)` | `|/<n>` |
| `abs(n)` | `@<n>` |
| `factorial(n)` | `!<n>` |
| `position(substring, string)` | `position(<substring> in <st`... |
| `substring(string, pattern, escape-None)` | `substring(<string> from <pa`... |
| `to_tsvector(arg1, document-None)` | `to_tsvector(<arg1>)` |
| `to_tsquery(arg1, text-None)` | `to_tsquery(<arg1>)` |
Usage:
```py
from buildpg import V, render, funcs
def show(component):
sql, params = render(':c', c=component)
print(f'sql="{sql}" params={params}')
show(funcs.AND(V('x') == 4, V('y') > 6))
#> sql="x = $1 AND y > $2" params=[4, 6]
show(funcs.position('foo', 'this has foo in it'))
#> sql="position($1 in $2)" params=['foo', 'this has foo in it']
```