parser: Generate correct types for SELECT NOT EXISTS

internal/compiler/output_columns.go

@@ -117,6 +117,23 @@ func outputColumns(qc *QueryCatalog, node ast.Node) ([]*Column, error) {
 				cols = append(cols, &Column{Name: name, DataType: "any", NotNull: false})
 			}
 
+		case *ast.BoolExpr:
+			name := ""
+			if res.Name != nil {
+				name = *res.Name
+			}
+			notNull := false
+			if n.Boolop == ast.BoolExprTypeNot && len(n.Args.Items) == 1 {
+				sublink, ok := n.Args.Items[0].(*ast.SubLink)
+				if ok && sublink.SubLinkType == ast.EXISTS_SUBLINK {
+					notNull = true
+					if name == "" {
+						name = "not_exists"
+					}
+				}
+			}
+			cols = append(cols, &Column{Name: name, DataType: "bool", NotNull: notNull})
+
 		case *ast.CaseExpr:
 			name := ""
 			if res.Name != nil {

internal/endtoend/testdata/select_not_exists/pgx/v4/query.sql

@@ -0,0 +1,12 @@
+CREATE TABLE bar (id serial not null);
+
+-- name: BarNotExists :one
+SELECT
+    NOT EXISTS (
+        SELECT
+            1
+        FROM
+            bar
+        where
+            id = $1
+    );

internal/endtoend/testdata/select_not_exists/pgx/v4/sqlc.json

@@ -0,0 +1,13 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "path": "go",
+      "engine": "postgresql",
+      "sql_package": "pgx/v4",
+      "name": "querytest",
+      "schema": "query.sql",
+      "queries": "query.sql"
+    }
+  ]
+}

internal/endtoend/testdata/select_not_exists/pgx/v5/query.sql

@@ -0,0 +1,12 @@
+CREATE TABLE bar (id serial not null);
+
+-- name: BarNotExists :one
+SELECT
+    NOT EXISTS (
+        SELECT
+            1
+        FROM
+            bar
+        where
+            id = $1
+    );

internal/endtoend/testdata/select_not_exists/pgx/v5/sqlc.json

@@ -0,0 +1,13 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "path": "go",
+      "engine": "postgresql",
+      "sql_package": "pgx/v5",
+      "name": "querytest",
+      "schema": "query.sql",
+      "queries": "query.sql"
+    }
+  ]
+}

internal/endtoend/testdata/select_not_exists/stdlib/query.sql

@@ -0,0 +1,12 @@
+CREATE TABLE bar (id serial not null);
+
+-- name: BarNotExists :one
+SELECT
+    NOT EXISTS (
+        SELECT
+            1
+        FROM
+            bar
+        where
+            id = $1
+    );

internal/endtoend/testdata/select_not_exists/stdlib/sqlc.json

@@ -0,0 +1,11 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "path": "go",
+      "name": "querytest",
+      "schema": "query.sql",
+      "queries": "query.sql"
+    }
+  ]
+}

internal/sql/ast/bool_expr_type.go

@@ -1,5 +1,13 @@
 package ast
 
+// https://github.com/pganalyze/libpg_query/blob/13-latest/protobuf/pg_query.proto#L2783-L2789
+const (
+	_ BoolExprType = iota
+	BoolExprTypeAnd
+	BoolExprTypeOr
+	BoolExprTypeNot
+)
+
 type BoolExprType uint
 
 func (n *BoolExprType) Pos() int {