diff --git a/private/db.rkt b/private/db.rkt
index c049594..f5ebd4e 100644
--- a/private/db.rkt
+++ b/private/db.rkt
@@ -4,7 +4,7 @@
 
 (provide
   (all-from-out db)
- 
+
   ;(rename-out [quasiquote DB]) ;; TODO try using struct types
 
   define-schema:
@@ -27,16 +27,12 @@
   (for-syntax
     typed/racket/base
     racket/syntax
-    (only-in racket/string string-split)
-    ;; --- query
-    (only-in racket/port with-input-from-string)
-    (only-in racket/format ~a)
-    racket/match
-    (for-syntax syntax/parse racket/syntax typed/racket/base)
     ;; --- ???
     syntax/parse
     syntax/stx
     trivial/private/common
+    trivial/private/db/schema
+    trivial/private/db/query
 ))
 
 (require/typed db
@@ -48,97 +44,10 @@
 
 ;; =============================================================================
 
+(define-syntax define-schema: (make-keyword-alias 'define schema-def))
+(define-syntax let-schema: (make-keyword-alias 'let schema-let))
+
 (begin-for-syntax
-
-  ;; -- schema = ((DB-NAME (ROW-TYPE ...))
-  ;;              ...)
-
-  (define (schema-parser stx)
-    (define x** (cadr (syntax->datum stx)))
-    (cond
-     [(and (list? x**)
-           (for/and ([x* (in-list x**)])
-             (and (= 2 (length x*))
-                  (symbol? (car x*))
-                  (list? (cadr x*))
-                  (for/and ([r (in-list (cadr x*))])
-                    (and (pair? r)
-                         (symbol? (car r))
-                         (symbol? (cdr r)))))))
-      x**]
-     [else #f]))
-
-  (define-values (schema-key schema? schema-def schema-let)
-    (make-value-property 'db:schema schema-parser))
-  (define-syntax-class/predicate schema/expand schema?)
-
-  (define (table-mem schema db)
-    (for/first ([tbl-schema (in-list schema)]
-                #:when (eq? db (car tbl-schema)))
-      (cadr tbl-schema)))
-
-  (define (row-mem tbl-schema row)
-    (for/first ([row-schema (in-list tbl-schema)]
-                #:when (eq? (car row-schema) row))
-      (cdr row-schema)))
-
-  (define (resolve-wildcard tbl-schema row)
-    (cond
-     [(eq? row '*)
-      (map car tbl-schema)]
-     [(list? row)
-      row]
-     [else
-      (list row)]))
-
-  (define (row-ref->type schema qrow)
-    (define q* (string-split qrow "."))
-    (case (length q*)
-     [(1)
-      ;; Make sure that row exists SOMEWHERE in table
-      (global-row-mem schema (string->symbol (car q*)))]
-     [(2)
-      ;; Have table name + row name, make sure they match
-      (let ([tbl (table-mem schema (string->symbol (car q*)))])
-        (and tbl (row-mem tbl (string->symbol (cadr q*)))))]
-     [else
-      (error 'internal-error "Failed to parse query-row '~a'" qrow)]))
-
-  (define (global-row-mem schema row)
-    (let loop ([acc #f]
-               [schema schema])
-      (cond
-       [(null? schema)
-        acc]
-       [(row-mem (cadr (car schema)) row)
-        => (lambda (t)
-        (if acc #f (loop t (cdr schema))))]
-       [else
-        (loop acc (cdr schema))])))
-
-  (define (condition*->type* schema condition* #:src stx)
-    (define unsorted
-      (for/fold ([acc '()])
-                ([condition (in-list condition*)])
-        (define typ (row-ref->type schema (car condition)))
-        (unless typ
-          (raise-syntax-error 'query-row:
-            "Failed to resolve type for row" (syntax->datum stx) condition))
-        (define val (cdr condition))
-        (define varnum (sql-variable? val))
-        (if varnum
-          (cons (cons typ varnum) acc)
-          acc)))
-    (for/list ([typ+num (sort unsorted string<? #:key cdr)]
-               [num (in-naturals 1)])
-      (unless (= (cdr typ+num) num)
-        (raise-syntax-error 'query-row:
-          (format "Missing query parameter '~a'" num)
-          (syntax->datum stx)))
-      (car typ+num)))
-
-  ;; --------------------------------------------------------------------------
-
   (define (connection-parser stx)
     ;; Connections have no primitive form -- need to use a wrapped API function
     #f)
@@ -146,67 +55,8 @@
   (define-values (connection-key connection? connection-def connection-let)
     (make-value-property 'db:connection connection-parser))
   (define-syntax-class/predicate connection/expand connection?)
-
-  ;; --------------------------------------------------------------------------
-  ;; -- query
-
-  (define (query-parser stx)
-    (define str (if (string? (syntax-e stx)) (syntax-e stx) (quoted-stx-value? stx)))
-    (and
-     (string? str)
-     (match (with-input-from-string (string-append "(" str ")") read)
-      [(list (? select?) sel (? from?) database rest* ...)
-       (define condition* (condition-parser rest*))
-       (list sel database condition*)]
-      [_ #f])))
-
-  (define (symbol-ci=? s1 s2)
-    (and
-     (symbol? s1)
-     (symbol? s2)
-     (string-ci=? (symbol->string s1) (symbol->string s2))))
-
-  (define-syntax (define-sql-keyword-predicate stx)
-    (syntax-parse stx
-     [(_ kwd*:id ...)
-      #:with (kwd?* ...) (for/list ([kwd (in-list (syntax-e #'(kwd* ...)))])
-                           (format-id stx "~a?" (syntax-e kwd)))
-      (syntax/loc stx
-        (begin (define (kwd?* v) (symbol-ci=? v 'kwd*)) ...))]))
-
-  (define-sql-keyword-predicate
-    select
-    from
-    where
-    and)
-
-  ;; Check for query parameters. Currently only for Postgres.
-  (define (sql-variable? s)
-    (define str (~a s))
-    (and
-      (= 2 (string-length str))
-      (eq? #\$ (string-ref str 0))
-      (string->number (string (string-ref str 1)))))
-
-  (define (condition-parser v*)
-    (let loop ([v* v*])
-      (match v*
-       ['()
-        '()]
-       [(list (or (? where?) (? and?)) db+row '= v rest* ...)
-        (cons (cons (~a db+row) (~a v))
-              (loop rest*))]
-       [(cons _ rest*)
-        (loop rest*)])))
-
-  (define-values (query-key query? query-def query-let)
-    (make-value-property 'db:query query-parser))
-  (define-syntax-class/predicate query/expand query?)
-
 )
 
-(define-syntax define-schema: (make-keyword-alias 'define schema-def))
-(define-syntax let-schema: (make-keyword-alias 'let schema-let))
 (define-syntax define-connection: (make-keyword-alias 'define connection-def))
 (define-syntax let-connection: (make-keyword-alias 'let connection-let))
 
@@ -220,6 +70,8 @@
       connection-key
       #'s.evidence)]))
 
+;; TODO query-maybe-row
+
 (define-syntax query-row: (make-alias #'query-row
   (lambda (stx) (syntax-parse stx
    [(_ c:connection/expand q:query/expand arg* ...)
@@ -229,8 +81,10 @@
     ;; -- Check connection vs. schema
     (define tbl-schema (table-mem schema table))
     (unless tbl-schema
-      (raise-syntax-error 'query-row "Unknown table" (syntax->datum stx) table))
+      (raise-syntax-error 'query-row: "Unknown table" (syntax->datum stx) table))
     (define row* (resolve-wildcard tbl-schema maybe-row*))
+    (when (null? row*)
+      (raise-syntax-error 'query-row: "Empty selection" (syntax->datum stx) 'q.expanded))
     (define result-type*
       (for/list ([r (in-list row*)])
         (or (row-mem tbl-schema r)
@@ -254,5 +108,5 @@
                 (vec-stx r-t* ...)))
         vector-length-key
         (length result-type*)))]
-  [_ #f]))))
+   [_ #f]))))
 
diff --git a/private/db/postgres.rkt b/private/db/postgres.rkt
new file mode 100644
index 0000000..d5b9c3f
--- /dev/null
+++ b/private/db/postgres.rkt
@@ -0,0 +1,123 @@
+#lang racket/base
+
+;; sql basics, belongs in a new file?
+
+(provide
+  postgres-parameter?
+  ;; (-> Any (Option Natural))
+  ;; If input is a Postgres parameter, return the parameter number.
+  ;;  i.e $2 -> 2
+  ;; Otherwise return #f.
+
+  ;; -- also exports predicates defined with `define-sql-keyword-predicate`
+)
+
+(require
+  (for-syntax
+    typed/racket/base
+    racket/syntax
+    syntax/parse))
+
+(define-syntax (define-sql-keyword-predicate stx)
+  (syntax-parse stx
+   [(_ kwd*:id ...)
+    #:with (kwd?* ...) (for/list ([kwd (in-list (syntax-e #'(kwd* ...)))])
+                         (format-id stx "~a?" (syntax-e kwd)))
+    (syntax/loc stx
+      (begin (begin (provide kwd?*) (define (kwd?* v) (symbol-ci=? v 'kwd*))) ...))]))
+
+;; -----------------------------------------------------------------------------
+
+(define (symbol-ci=? s1 s2)
+  (and
+   (symbol? s1)
+   (symbol? s2)
+   (string-ci=? (symbol->string s1) (symbol->string s2))))
+
+(define-sql-keyword-predicate
+  select
+  from
+  where
+  and)
+
+;; Check for query parameters. Currently only for Postgres.
+(define (postgres-parameter? s)
+  (and
+   (or (string? s) (symbol? s))
+   (let ([str (if (string? s) s (symbol->string s))])
+     (and
+      (= 2 (string-length str))
+      (eq? #\$ (string-ref str 0))
+      (string->number (string (string-ref str 1)))))))
+
+(module+ test
+  (require rackunit rackunit-abbrevs)
+
+  (check-apply* symbol-ci=?
+   ['a 'a
+    => #t]
+   ['a 'A
+    => #t]
+   ['yellow 'YeLLOW
+    => #t]
+   ['wait 'forME
+    => #f]
+   ['x 'y
+    => #f]
+   ["A" 'A
+    => #f]
+   [315 "bage"
+    => #f]
+  )
+
+  (check-apply* select?
+   ['select
+    => #t]
+   ['SELECT
+    => #t]
+   ['yolo
+    => #f]
+  )
+
+  (check-apply* from?
+   ['from
+    => #t]
+   ['FROM
+    => #t]
+   ['yolo
+    => #f]
+  )
+
+  (check-apply* where?
+   ['where
+    => #t]
+   ['WHERE
+    => #t]
+   ['yolo
+    => #f]
+  )
+
+  (check-apply* and?
+   ['and
+    => #t]
+   ['AND
+    => #t]
+   ['yolo
+    => #f]
+  )
+
+  (check-apply* postgres-parameter?
+   ["$1"
+    => 1]
+   ['$1
+    => 1]
+   ["$125"
+    => #f]
+   ['$555
+    => #f]
+   ['wepa
+    => #f]
+   [3
+    => #f]
+  )
+)
diff --git a/private/db/query.rkt b/private/db/query.rkt
index b9e9288..305d623 100644
--- a/private/db/query.rkt
+++ b/private/db/query.rkt
@@ -10,6 +10,7 @@
 (require
   trivial/private/common
   trivial/private/db/schema
+  trivial/private/db/postgres
   (only-in racket/port with-input-from-string)
   (only-in racket/format ~a)
   (only-in racket/string string-replace)
diff --git a/private/db/schema.rkt b/private/db/schema.rkt
index 25d61ce..e7289f0 100644
--- a/private/db/schema.rkt
+++ b/private/db/schema.rkt
@@ -7,17 +7,20 @@
 
 
 (provide
+  condition*->type*
+  resolve-wildcard
+  row-mem
+  table-mem
+  ;; --
   schema-def
   schema-let
+  schema/expand
 )
 
 (require
   trivial/private/common
+  trivial/private/db/postgres
   (only-in racket/string string-split)
-  (for-syntax
-    typed/racket/base
-    racket/syntax
-    syntax/parse)
 )
 
 ;; =============================================================================
@@ -47,37 +50,6 @@
   (make-value-property 'db:schema schema-parser))
 (define-syntax-class/predicate schema/expand schema?)
 
-;; -----------------------------------------------------------------------------
-;; sql basics, belongs in a new file?
-
-(define (symbol-ci=? s1 s2)
-  (and
-   (symbol? s1)
-   (symbol? s2)
-   (string-ci=? (symbol->string s1) (symbol->string s2))))
-
-(define-syntax (define-sql-keyword-predicate stx)
-  (syntax-parse stx
-   [(_ kwd*:id ...)
-    #:with (kwd?* ...) (for/list ([kwd (in-list (syntax-e #'(kwd* ...)))])
-                         (format-id stx "~a?" (syntax-e kwd)))
-    (syntax/loc stx
-      (begin (define (kwd?* v) (symbol-ci=? v 'kwd*)) ...))]))
-
-(define-sql-keyword-predicate
-  select
-  from
-  where
-  and)
-
-;; Check for query parameters. Currently only for Postgres.
-(define (sql-variable? s)
-  (define str (if (string? s) s (symbol->string s)))
-  (and
-    (= 2 (string-length str))
-    (eq? #\$ (string-ref str 0))
-    (string->number (string (string-ref str 1)))))
-
 ;; -----------------------------------------------------------------------------
 
 ;(: table-mem (-> DbSchema TableName (Option TableSchema)))
@@ -135,7 +107,7 @@
         (raise-syntax-error 'query-row:
           "Failed to resolve type for row" (syntax->datum stx) condition))
       (define val (cdr condition))
-      (define varnum (sql-variable? val))
+      (define varnum (postgres-parameter? val))
       (if varnum
         (cons (cons typ varnum) acc)
         acc)))
@@ -164,74 +136,6 @@
    [#'(quote ((Foo ((Bar . Baz)))))]
   )
 
-  (check-apply* symbol-ci=?
-   ['a 'a
-    => #t]
-   ['a 'A
-    => #t]
-   ['yellow 'YeLLOW
-    => #t]
-   ['wait 'forME
-    => #f]
-   ['x 'y
-    => #f]
-   ["A" 'A
-    => #f]
-   [315 "bage"
-    => #f]
-  )
-
-  (check-apply* select?
-   ['select
-    => #t]
-   ['SELECT
-    => #t]
-   ['yolo
-    => #f]
-  )
-
-  (check-apply* from?
-   ['from
-    => #t]
-   ['FROM
-    => #t]
-   ['yolo
-    => #f]
-  )
-
-  (check-apply* where?
-   ['where
-    => #t]
-   ['WHERE
-    => #t]
-   ['yolo
-    => #f]
-  )
-
-  (check-apply* and?
-   ['and
-    => #t]
-   ['AND
-    => #t]
-   ['yolo
-    => #f]
-  )
-
-  (check-apply* sql-variable?
-   ["$1"
-    => 1]
-   ['$1
-    => 1]
-   ["$125"
-    => #f]
-   ['$555
-    => #f]
-   ['wepa
-    => #f]
-  )
-  (check-exn exn:fail:contract?
-    (lambda () (sql-variable? 3)))
-
   (check-apply* table-mem
    ['((a ((b . c)))) 'a
     =>  '((b . c))]