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from sqlalchemy.exc import CompileError
from sqlalchemy.sql.compiler import SQLCompiler
from clickhouse_connect.cc_sqlalchemy.sql import format_table
# pylint: disable=arguments-differ
class ChStatementCompiler(SQLCompiler):
# pylint: disable=attribute-defined-outside-init
def visit_delete(self, delete_stmt, visiting_cte=None, **kw):
table = delete_stmt.table
text = f"DELETE FROM {format_table(table)}"
if delete_stmt.whereclause is not None:
self._in_delete_where = True
try:
text += " WHERE " + self.process(delete_stmt.whereclause, **kw)
finally:
self._in_delete_where = False
else:
raise CompileError("ClickHouse DELETE statements require a WHERE clause. To delete all rows, use 'TRUNCATE TABLE' instead.")
return text
def visit_select(self, select_stmt, **kw):
return super().visit_select(select_stmt, **kw)
def visit_join(self, join, **kw):
left = self.process(join.left, **kw)
right = self.process(join.right, **kw)
onclause = join.onclause
if getattr(join, "full", False):
join_kw = " FULL OUTER JOIN "
elif onclause is None:
join_kw = " CROSS JOIN "
elif join.isouter:
join_kw = " LEFT OUTER JOIN "
else:
join_kw = " INNER JOIN "
text = left + join_kw + right
if onclause is not None:
text += " ON " + self.process(onclause, **kw)
return text
def visit_column(self, column, add_to_result_map=None, include_table=True, result_map_targets=(), ambiguous_table_name_map=None, **kw):
if getattr(self, "_in_delete_where", False):
return self.preparer.quote(column.name)
return super().visit_column(
column,
add_to_result_map=add_to_result_map,
include_table=include_table,
result_map_targets=result_map_targets,
**kw,
)
# Abstract methods required by SQLCompiler
def delete_extra_from_clause(self, delete_stmt, from_table, extra_froms, from_hints, **kw):
raise NotImplementedError("ClickHouse doesn't support DELETE with extra FROM clause")
def update_from_clause(self, update_stmt, from_table, extra_froms, from_hints, **kw):
raise NotImplementedError("ClickHouse doesn't support UPDATE with FROM clause")
# pylint: disable=unused-argument
def visit_empty_set_expr(self, element_types, **kw):
return "SELECT 1 WHERE 1=0"
def visit_sequence(self, sequence, **kw):
raise NotImplementedError("ClickHouse doesn't support sequences")
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