feat(postgresql): Support system columns on tables (#2871)

* test: Add a test case for #1745

* feat(postgresql): Support system columns

* Remove stdlib

* Update sqlc.yaml

* Add exec.json

---------

Co-authored-by: Andrew Benton <andrew@sqlc.dev>

internal/endtoend/testdata/select_system/issue.md

@@ -0,0 +1 @@
+https://github.com/sqlc-dev/sqlc/issues/1745

internal/endtoend/testdata/select_system/pgx/exec.json

@@ -0,0 +1,3 @@
+{
+    "contexts": ["managed-db"]
+}

internal/endtoend/testdata/select_system/pgx/query.sql

@@ -0,0 +1,4 @@
+-- name: GetSystemColumns :one
+SELECT
+  tableoid, xmin, cmin, xmax, cmax, ctid
+FROM test;

internal/endtoend/testdata/select_system/pgx/schema.sql

@@ -0,0 +1,3 @@
+CREATE TABLE test (
+  id INT
+);

internal/endtoend/testdata/select_system/pgx/sqlc.yaml

@@ -0,0 +1,10 @@
+version: "2"
+sql:
+  - engine: "postgresql"
+    schema: "schema.sql"
+    queries: "query.sql"
+    gen:
+      go:
+        package: "querytest"
+        out: "go"
+        sql_package: "pgx/v5"

internal/engine/postgresql/analyzer/analyze.go

@@ -101,7 +101,7 @@ func (a *Analyzer) columnInfo(ctx context.Context, field pgconn.FieldDescription
 	if ok {
 		return cinfo.(*pgColumn), nil
 	}
-	rows, err := a.pool.Query(ctx, columnQuery, field.TableOID, field.TableAttributeNumber)
+	rows, err := a.pool.Query(ctx, columnQuery, field.TableOID, int16(field.TableAttributeNumber))
 	if err != nil {
 		return nil, err
 	}