diff --git a/crates/squawk_parser/tests/data/ok/merge.sql b/crates/squawk_parser/tests/data/ok/merge.sql
index da448883..f2d13d3f 100644
--- a/crates/squawk_parser/tests/data/ok/merge.sql
+++ b/crates/squawk_parser/tests/data/ok/merge.sql
@@ -150,8 +150,6 @@ merge into t
       b = 1,
       c = d,
       e = (select 1),
-      f = row(1, 2, default),
-      g = (1, 2, default),
       h = (default)
   when not matched by source then
     update set foo = bar;
diff --git a/crates/squawk_parser/tests/data/ok/select.sql b/crates/squawk_parser/tests/data/ok/select.sql
index 26381e9c..4ba845f9 100644
--- a/crates/squawk_parser/tests/data/ok/select.sql
+++ b/crates/squawk_parser/tests/data/ok/select.sql
@@ -464,7 +464,6 @@ select 1 collate;
 select foo.bar null;
 select foo.bar default;
 
-select default;
 select c default;
 select null;
 select c null;
diff --git a/crates/squawk_parser/tests/snapshots/tests__merge_ok.snap b/crates/squawk_parser/tests/snapshots/tests__merge_ok.snap
index e021a975..f26bcf92 100644
--- a/crates/squawk_parser/tests/snapshots/tests__merge_ok.snap
+++ b/crates/squawk_parser/tests/snapshots/tests__merge_ok.snap
@@ -1420,55 +1420,6 @@ SOURCE_FILE
                   R_PAREN ")"
             COMMA ","
             WHITESPACE "\n      "
-            SET_SINGLE_COLUMN
-              COLUMN
-                NAME_REF
-                  IDENT "f"
-              WHITESPACE " "
-              EQ "="
-              WHITESPACE " "
-              SET_EXPR
-                CALL_EXPR
-                  NAME_REF
-                    ROW_KW "row"
-                  ARG_LIST
-                    L_PAREN "("
-                    LITERAL
-                      INT_NUMBER "1"
-                    COMMA ","
-                    WHITESPACE " "
-                    LITERAL
-                      INT_NUMBER "2"
-                    COMMA ","
-                    WHITESPACE " "
-                    LITERAL
-                      DEFAULT_KW "default"
-                    R_PAREN ")"
-            COMMA ","
-            WHITESPACE "\n      "
-            SET_SINGLE_COLUMN
-              COLUMN
-                NAME_REF
-                  IDENT "g"
-              WHITESPACE " "
-              EQ "="
-              WHITESPACE " "
-              SET_EXPR
-                TUPLE_EXPR
-                  L_PAREN "("
-                  LITERAL
-                    INT_NUMBER "1"
-                  COMMA ","
-                  WHITESPACE " "
-                  LITERAL
-                    INT_NUMBER "2"
-                  COMMA ","
-                  WHITESPACE " "
-                  LITERAL
-                    DEFAULT_KW "default"
-                  R_PAREN ")"
-            COMMA ","
-            WHITESPACE "\n      "
             SET_SINGLE_COLUMN
               COLUMN
                 NAME_REF
diff --git a/crates/squawk_parser/tests/snapshots/tests__select_ok.snap b/crates/squawk_parser/tests/snapshots/tests__select_ok.snap
index b26d998f..f783cef5 100644
--- a/crates/squawk_parser/tests/snapshots/tests__select_ok.snap
+++ b/crates/squawk_parser/tests/snapshots/tests__select_ok.snap
@@ -5863,16 +5863,6 @@ SOURCE_FILE
               DEFAULT_KW "default"
     SEMICOLON ";"
   WHITESPACE "\n\n"
-  SELECT
-    SELECT_CLAUSE
-      SELECT_KW "select"
-      WHITESPACE " "
-      TARGET_LIST
-        TARGET
-          LITERAL
-            DEFAULT_KW "default"
-    SEMICOLON ";"
-  WHITESPACE "\n"
   SELECT
     SELECT_CLAUSE
       SELECT_KW "select"
diff --git a/crates/squawk_syntax/src/ast/generated/nodes.rs b/crates/squawk_syntax/src/ast/generated/nodes.rs
index b414d1d6..d3b986de 100644
--- a/crates/squawk_syntax/src/ast/generated/nodes.rs
+++ b/crates/squawk_syntax/src/ast/generated/nodes.rs
@@ -3172,6 +3172,10 @@ impl Column {
         support::child(&self.syntax)
     }
     #[inline]
+    pub fn field_expr(&self) -> Option<FieldExpr> {
+        support::child(&self.syntax)
+    }
+    #[inline]
     pub fn index_expr(&self) -> Option<IndexExpr> {
         support::child(&self.syntax)
     }
diff --git a/crates/squawk_syntax/src/postgresql.ungram b/crates/squawk_syntax/src/postgresql.ungram
index 2cd387ad..47bd4cd6 100644
--- a/crates/squawk_syntax/src/postgresql.ungram
+++ b/crates/squawk_syntax/src/postgresql.ungram
@@ -675,6 +675,7 @@ Column =
       NotEnforced? Enforced?
   | 'period'? NameRef
   | IndexExpr
+  | FieldExpr
   )
 ColumnConstraint =
   CheckConstraint
diff --git a/crates/squawk_syntax/src/snapshots/squawk_syntax__test__default_ok_validation.snap b/crates/squawk_syntax/src/snapshots/squawk_syntax__test__default_ok_validation.snap
new file mode 100644
index 00000000..73f6cc0f
--- /dev/null
+++ b/crates/squawk_syntax/src/snapshots/squawk_syntax__test__default_ok_validation.snap
@@ -0,0 +1,388 @@
+---
+source: crates/squawk_syntax/src/test.rs
+input_file: crates/squawk_syntax/test_data/validation/default_ok.sql
+---
+SOURCE_FILE@0..492
+  UPDATE@0..27
+    UPDATE_KW@0..6 "UPDATE"
+    WHITESPACE@6..7 " "
+    RELATION_NAME@7..8
+      PATH@7..8
+        PATH_SEGMENT@7..8
+          NAME_REF@7..8
+            IDENT@7..8 "t"
+    WHITESPACE@8..9 " "
+    SET_CLAUSE@9..26
+      SET_KW@9..12 "SET"
+      WHITESPACE@12..13 " "
+      SET_COLUMN_LIST@13..26
+        SET_SINGLE_COLUMN@13..26
+          COLUMN@13..16
+            NAME_REF@13..16
+              IDENT@13..16 "col"
+          WHITESPACE@16..17 " "
+          EQ@17..18 "="
+          WHITESPACE@18..19 " "
+          SET_EXPR@19..26
+            DEFAULT_KW@19..26 "DEFAULT"
+    SEMICOLON@26..27 ";"
+  WHITESPACE@27..29 "\n\n"
+  UPDATE@29..63
+    UPDATE_KW@29..35 "UPDATE"
+    WHITESPACE@35..36 " "
+    RELATION_NAME@36..37
+      PATH@36..37
+        PATH_SEGMENT@36..37
+          NAME_REF@36..37
+            IDENT@36..37 "t"
+    WHITESPACE@37..38 " "
+    SET_CLAUSE@38..62
+      SET_KW@38..41 "SET"
+      WHITESPACE@41..42 " "
+      SET_COLUMN_LIST@42..62
+        SET_MULTIPLE_COLUMNS@42..62
+          COLUMN_LIST@42..47
+            L_PAREN@42..43 "("
+            COLUMN@43..44
+              NAME_REF@43..44
+                IDENT@43..44 "a"
+            COMMA@44..45 ","
+            COLUMN@45..46
+              NAME_REF@45..46
+                IDENT@45..46 "b"
+            R_PAREN@46..47 ")"
+          WHITESPACE@47..48 " "
+          EQ@48..49 "="
+          WHITESPACE@49..50 " "
+          SET_EXPR_LIST@50..62
+            L_PAREN@50..51 "("
+            SET_EXPR@51..58
+              DEFAULT_KW@51..58 "DEFAULT"
+            COMMA@58..59 ","
+            WHITESPACE@59..60 " "
+            SET_EXPR@60..61
+              LITERAL@60..61
+                INT_NUMBER@60..61 "1"
+            R_PAREN@61..62 ")"
+    SEMICOLON@62..63 ";"
+  WHITESPACE@63..65 "\n\n"
+  INSERT@65..96
+    INSERT_KW@65..71 "INSERT"
+    WHITESPACE@71..72 " "
+    INTO_KW@72..76 "into"
+    WHITESPACE@76..77 " "
+    PATH@77..78
+      PATH_SEGMENT@77..78
+        NAME_REF@77..78
+          IDENT@77..78 "t"
+    WHITESPACE@78..79 " "
+    VALUES@79..95
+      VALUES_KW@79..85 "VALUES"
+      WHITESPACE@85..86 " "
+      ROW_LIST@86..95
+        ROW@86..95
+          L_PAREN@86..87 "("
+          LITERAL@87..94
+            DEFAULT_KW@87..94 "DEFAULT"
+          R_PAREN@94..95 ")"
+    SEMICOLON@95..96 ";"
+  WHITESPACE@96..98 "\n\n"
+  MERGE@98..240
+    MERGE_KW@98..103 "MERGE"
+    WHITESPACE@103..104 " "
+    INTO_KW@104..108 "INTO"
+    WHITESPACE@108..109 " "
+    RELATION_NAME@109..115
+      PATH@109..115
+        PATH_SEGMENT@109..115
+          NAME_REF@109..115
+            TARGET_KW@109..115 "target"
+    WHITESPACE@115..116 " "
+    ALIAS@116..117
+      NAME@116..117
+        IDENT@116..117 "t"
+    WHITESPACE@117..120 "\n  "
+    USING_ON_CLAUSE@120..154
+      USING_KW@120..125 "USING"
+      WHITESPACE@125..126 " "
+      FROM_ITEM@126..134
+        NAME_REF@126..132
+          SOURCE_KW@126..132 "source"
+        WHITESPACE@132..133 " "
+        ALIAS@133..134
+          NAME@133..134
+            IDENT@133..134 "s"
+      WHITESPACE@134..140 "\n     "
+      ON_CLAUSE@140..154
+        ON_KW@140..142 "ON"
+        WHITESPACE@142..143 " "
+        BIN_EXPR@143..154
+          FIELD_EXPR@143..147
+            NAME_REF@143..144
+              IDENT@143..144 "t"
+            DOT@144..145 "."
+            NAME_REF@145..147
+              IDENT@145..147 "id"
+          WHITESPACE@147..148 " "
+          EQ@148..149 "="
+          WHITESPACE@149..150 " "
+          FIELD_EXPR@150..154
+            NAME_REF@150..151
+              IDENT@150..151 "s"
+            DOT@151..152 "."
+            NAME_REF@152..154
+              IDENT@152..154 "id"
+    WHITESPACE@154..157 "\n  "
+    MERGE_WHEN_NOT_MATCHED_TARGET@157..239
+      WHEN_KW@157..161 "WHEN"
+      WHITESPACE@161..162 " "
+      NOT_KW@162..165 "NOT"
+      WHITESPACE@165..166 " "
+      MATCHED_KW@166..173 "MATCHED"
+      WHITESPACE@173..174 " "
+      THEN_KW@174..178 "THEN"
+      WHITESPACE@178..185 "\n      "
+      MERGE_INSERT@185..239
+        INSERT_KW@185..191 "INSERT"
+        WHITESPACE@191..192 " "
+        COLUMN_LIST@192..207
+          L_PAREN@192..193 "("
+          COLUMN@193..195
+            NAME_REF@193..195
+              IDENT@193..195 "id"
+          COMMA@195..196 ","
+          WHITESPACE@196..197 " "
+          COLUMN@197..201
+            NAME_REF@197..201
+              NAME_KW@197..201 "name"
+          COMMA@201..202 ","
+          WHITESPACE@202..203 " "
+          COLUMN@203..206
+            NAME_REF@203..206
+              IDENT@203..206 "qty"
+          R_PAREN@206..207 ")"
+        WHITESPACE@207..208 " "
+        VALUES@208..239
+          VALUES_KW@208..214 "VALUES"
+          WHITESPACE@214..215 " "
+          ROW_LIST@215..239
+            ROW@215..239
+              L_PAREN@215..216 "("
+              FIELD_EXPR@216..220
+                NAME_REF@216..217
+                  IDENT@216..217 "s"
+                DOT@217..218 "."
+                NAME_REF@218..220
+                  IDENT@218..220 "id"
+              COMMA@220..221 ","
+              WHITESPACE@221..222 " "
+              LITERAL@222..229
+                DEFAULT_KW@222..229 "DEFAULT"
+              COMMA@229..230 ","
+              WHITESPACE@230..231 " "
+              LITERAL@231..238
+                DEFAULT_KW@231..238 "DEFAULT"
+              R_PAREN@238..239 ")"
+    SEMICOLON@239..240 ";"
+  WHITESPACE@240..242 "\n\n"
+  MERGE@242..351
+    MERGE_KW@242..247 "MERGE"
+    WHITESPACE@247..248 " "
+    INTO_KW@248..252 "INTO"
+    WHITESPACE@252..253 " "
+    RELATION_NAME@253..259
+      PATH@253..259
+        PATH_SEGMENT@253..259
+          NAME_REF@253..259
+            TARGET_KW@253..259 "target"
+    WHITESPACE@259..260 " "
+    ALIAS@260..261
+      NAME@260..261
+        IDENT@260..261 "t"
+    WHITESPACE@261..264 "\n  "
+    USING_ON_CLAUSE@264..298
+      USING_KW@264..269 "USING"
+      WHITESPACE@269..270 " "
+      FROM_ITEM@270..278
+        NAME_REF@270..276
+          SOURCE_KW@270..276 "source"
+        WHITESPACE@276..277 " "
+        ALIAS@277..278
+          NAME@277..278
+            IDENT@277..278 "s"
+      WHITESPACE@278..284 "\n     "
+      ON_CLAUSE@284..298
+        ON_KW@284..286 "ON"
+        WHITESPACE@286..287 " "
+        BIN_EXPR@287..298
+          FIELD_EXPR@287..291
+            NAME_REF@287..288
+              IDENT@287..288 "t"
+            DOT@288..289 "."
+            NAME_REF@289..291
+              IDENT@289..291 "id"
+          WHITESPACE@291..292 " "
+          EQ@292..293 "="
+          WHITESPACE@293..294 " "
+          FIELD_EXPR@294..298
+            NAME_REF@294..295
+              IDENT@294..295 "s"
+            DOT@295..296 "."
+            NAME_REF@296..298
+              IDENT@296..298 "id"
+    WHITESPACE@298..301 "\n  "
+    MERGE_WHEN_MATCHED@301..350
+      WHEN_KW@301..305 "WHEN"
+      WHITESPACE@305..306 " "
+      MATCHED_KW@306..313 "MATCHED"
+      WHITESPACE@313..314 " "
+      THEN_KW@314..318 "THEN"
+      WHITESPACE@318..325 "\n      "
+      MERGE_UPDATE@325..350
+        UPDATE_KW@325..331 "UPDATE"
+        WHITESPACE@331..332 " "
+        SET_CLAUSE@332..350
+          SET_KW@332..335 "SET"
+          WHITESPACE@335..336 " "
+          SET_COLUMN_LIST@336..350
+            SET_SINGLE_COLUMN@336..350
+              COLUMN@336..340
+                NAME_REF@336..340
+                  IDENT@336..340 "qty2"
+              WHITESPACE@340..341 " "
+              EQ@341..342 "="
+              WHITESPACE@342..343 " "
+              SET_EXPR@343..350
+                DEFAULT_KW@343..350 "DEFAULT"
+    SEMICOLON@350..351 ";"
+  WHITESPACE@351..353 "\n\n"
+  UPDATE@353..382
+    UPDATE_KW@353..359 "UPDATE"
+    WHITESPACE@359..360 " "
+    RELATION_NAME@360..361
+      PATH@360..361
+        PATH_SEGMENT@360..361
+          NAME_REF@360..361
+            IDENT@360..361 "t"
+    WHITESPACE@361..362 " "
+    SET_CLAUSE@362..381
+      SET_KW@362..365 "SET"
+      WHITESPACE@365..366 " "
+      SET_COLUMN_LIST@366..381
+        SET_SINGLE_COLUMN@366..381
+          COLUMN@366..369
+            NAME_REF@366..369
+              IDENT@366..369 "col"
+          WHITESPACE@369..370 " "
+          EQ@370..371 "="
+          WHITESPACE@371..372 " "
+          SET_EXPR@372..381
+            PAREN_EXPR@372..381
+              L_PAREN@372..373 "("
+              LITERAL@373..380
+                DEFAULT_KW@373..380 "DEFAULT"
+              R_PAREN@380..381 ")"
+    SEMICOLON@381..382 ";"
+  WHITESPACE@382..384 "\n\n"
+  UPDATE@384..417
+    UPDATE_KW@384..390 "UPDATE"
+    WHITESPACE@390..391 " "
+    RELATION_NAME@391..392
+      PATH@391..392
+        PATH_SEGMENT@391..392
+          NAME_REF@391..392
+            IDENT@391..392 "t"
+    WHITESPACE@392..393 " "
+    SET_CLAUSE@393..416
+      SET_KW@393..396 "SET"
+      WHITESPACE@396..397 " "
+      SET_COLUMN_LIST@397..416
+        SET_SINGLE_COLUMN@397..416
+          COLUMN@397..400
+            NAME_REF@397..400
+              IDENT@397..400 "col"
+          WHITESPACE@400..401 " "
+          EQ@401..402 "="
+          WHITESPACE@402..403 " "
+          SET_EXPR@403..416
+            PAREN_EXPR@403..416
+              L_PAREN@403..404 "("
+              PAREN_EXPR@404..415
+                L_PAREN@404..405 "("
+                PAREN_EXPR@405..414
+                  L_PAREN@405..406 "("
+                  LITERAL@406..413
+                    DEFAULT_KW@406..413 "DEFAULT"
+                  R_PAREN@413..414 ")"
+                R_PAREN@414..415 ")"
+              R_PAREN@415..416 ")"
+    SEMICOLON@416..417 ";"
+  WHITESPACE@417..419 "\n\n"
+  UPDATE@419..456
+    UPDATE_KW@419..425 "UPDATE"
+    WHITESPACE@425..426 " "
+    RELATION_NAME@426..427
+      PATH@426..427
+        PATH_SEGMENT@426..427
+          NAME_REF@426..427
+            IDENT@426..427 "t"
+    WHITESPACE@427..428 " "
+    SET_CLAUSE@428..455
+      SET_KW@428..431 "SET"
+      WHITESPACE@431..432 " "
+      SET_COLUMN_LIST@432..455
+        SET_MULTIPLE_COLUMNS@432..455
+          COLUMN_LIST@432..438
+            L_PAREN@432..433 "("
+            COLUMN@433..434
+              NAME_REF@433..434
+                IDENT@433..434 "a"
+            COMMA@434..435 ","
+            WHITESPACE@435..436 " "
+            COLUMN@436..437
+              NAME_REF@436..437
+                IDENT@436..437 "b"
+            R_PAREN@437..438 ")"
+          WHITESPACE@438..439 " "
+          EQ@439..440 "="
+          WHITESPACE@440..441 " "
+          SET_EXPR_LIST@441..455
+            L_PAREN@441..442 "("
+            SET_EXPR@442..451
+              PAREN_EXPR@442..451
+                L_PAREN@442..443 "("
+                LITERAL@443..450
+                  DEFAULT_KW@443..450 "DEFAULT"
+                R_PAREN@450..451 ")"
+            COMMA@451..452 ","
+            WHITESPACE@452..453 " "
+            SET_EXPR@453..454
+              LITERAL@453..454
+                INT_NUMBER@453..454 "1"
+            R_PAREN@454..455 ")"
+    SEMICOLON@455..456 ";"
+  WHITESPACE@456..458 "\n\n"
+  INSERT@458..491
+    INSERT_KW@458..464 "INSERT"
+    WHITESPACE@464..465 " "
+    INTO_KW@465..469 "INTO"
+    WHITESPACE@469..470 " "
+    PATH@470..471
+      PATH_SEGMENT@470..471
+        NAME_REF@470..471
+          IDENT@470..471 "t"
+    WHITESPACE@471..472 " "
+    VALUES@472..490
+      VALUES_KW@472..478 "VALUES"
+      WHITESPACE@478..479 " "
+      ROW_LIST@479..490
+        ROW@479..490
+          L_PAREN@479..480 "("
+          PAREN_EXPR@480..489
+            L_PAREN@480..481 "("
+            LITERAL@481..488
+              DEFAULT_KW@481..488 "DEFAULT"
+            R_PAREN@488..489 ")"
+          R_PAREN@489..490 ")"
+    SEMICOLON@490..491 ";"
+  WHITESPACE@491..492 "\n"
diff --git a/crates/squawk_syntax/src/snapshots/squawk_syntax__test__default_validation.snap b/crates/squawk_syntax/src/snapshots/squawk_syntax__test__default_validation.snap
new file mode 100644
index 00000000..3ba19249
--- /dev/null
+++ b/crates/squawk_syntax/src/snapshots/squawk_syntax__test__default_validation.snap
@@ -0,0 +1,157 @@
+---
+source: crates/squawk_syntax/src/test.rs
+input_file: crates/squawk_syntax/test_data/validation/default.sql
+---
+SOURCE_FILE@0..170
+  INSERT@0..36
+    INSERT_KW@0..6 "insert"
+    WHITESPACE@6..7 " "
+    INTO_KW@7..11 "into"
+    WHITESPACE@11..12 " "
+    PATH@12..13
+      PATH_SEGMENT@12..13
+        NAME_REF@12..13
+          IDENT@12..13 "t"
+    WHITESPACE@13..14 " "
+    VALUES@14..35
+      VALUES_KW@14..20 "VALUES"
+      WHITESPACE@20..21 " "
+      ROW_LIST@21..35
+        ROW@21..35
+          L_PAREN@21..22 "("
+          CALL_EXPR@22..34
+            NAME_REF@22..25
+              IDENT@22..25 "foo"
+            ARG_LIST@25..34
+              L_PAREN@25..26 "("
+              LITERAL@26..33
+                DEFAULT_KW@26..33 "DEFAULT"
+              R_PAREN@33..34 ")"
+          R_PAREN@34..35 ")"
+    SEMICOLON@35..36 ";"
+  WHITESPACE@36..38 "\n\n"
+  UPDATE@38..68
+    UPDATE_KW@38..44 "UPDATE"
+    WHITESPACE@44..45 " "
+    RELATION_NAME@45..46
+      PATH@45..46
+        PATH_SEGMENT@45..46
+          NAME_REF@45..46
+            IDENT@45..46 "t"
+    WHITESPACE@46..47 " "
+    SET_CLAUSE@47..67
+      SET_KW@47..50 "SET"
+      WHITESPACE@50..51 " "
+      SET_COLUMN_LIST@51..67
+        SET_SINGLE_COLUMN@51..67
+          COLUMN@51..57
+            INDEX_EXPR@51..57
+              NAME_REF@51..54
+                IDENT@51..54 "arr"
+              L_BRACK@54..55 "["
+              LITERAL@55..56
+                INT_NUMBER@55..56 "1"
+              R_BRACK@56..57 "]"
+          WHITESPACE@57..58 " "
+          EQ@58..59 "="
+          WHITESPACE@59..60 " "
+          SET_EXPR@60..67
+            DEFAULT_KW@60..67 "DEFAULT"
+    SEMICOLON@67..68 ";"
+  WHITESPACE@68..70 "\n\n"
+  UPDATE@70..104
+    UPDATE_KW@70..76 "UPDATE"
+    WHITESPACE@76..77 " "
+    RELATION_NAME@77..78
+      PATH@77..78
+        PATH_SEGMENT@77..78
+          NAME_REF@77..78
+            IDENT@77..78 "t"
+    WHITESPACE@78..79 " "
+    SET_CLAUSE@79..103
+      SET_KW@79..82 "SET"
+      WHITESPACE@82..83 " "
+      SET_COLUMN_LIST@83..103
+        SET_SINGLE_COLUMN@83..103
+          COLUMN@83..93
+            FIELD_EXPR@83..93
+              NAME_REF@83..87
+                IDENT@83..87 "comp"
+              DOT@87..88 "."
+              NAME_REF@88..93
+                IDENT@88..93 "field"
+          WHITESPACE@93..94 " "
+          EQ@94..95 "="
+          WHITESPACE@95..96 " "
+          SET_EXPR@96..103
+            DEFAULT_KW@96..103 "DEFAULT"
+    SEMICOLON@103..104 ";"
+  WHITESPACE@104..106 "\n\n"
+  VALUES@106..123
+    VALUES_KW@106..112 "values"
+    WHITESPACE@112..113 " "
+    ROW_LIST@113..122
+      ROW@113..122
+        L_PAREN@113..114 "("
+        LITERAL@114..121
+          DEFAULT_KW@114..121 "default"
+        R_PAREN@121..122 ")"
+    SEMICOLON@122..123 ";"
+  WHITESPACE@123..125 "\n\n"
+  SELECT@125..140
+    SELECT_CLAUSE@125..139
+      SELECT_KW@125..131 "select"
+      WHITESPACE@131..132 " "
+      TARGET_LIST@132..139
+        TARGET@132..139
+          LITERAL@132..139
+            DEFAULT_KW@132..139 "default"
+    SEMICOLON@139..140 ";"
+  WHITESPACE@140..142 "\n\n"
+  SELECT@142..169
+    SELECT_CLAUSE@142..150
+      SELECT_KW@142..148 "select"
+      WHITESPACE@148..149 " "
+      TARGET_LIST@149..150
+        TARGET@149..150
+          LITERAL@149..150
+            INT_NUMBER@149..150 "1"
+    WHITESPACE@150..151 " "
+    WHERE_CLAUSE@151..168
+      WHERE_KW@151..156 "where"
+      WHITESPACE@156..157 " "
+      BIN_EXPR@157..168
+        LITERAL@157..164
+          DEFAULT_KW@157..164 "default"
+        WHITESPACE@164..165 " "
+        EQ@165..166 "="
+        WHITESPACE@166..167 " "
+        LITERAL@167..168
+          INT_NUMBER@167..168 "1"
+    SEMICOLON@168..169 ";"
+  WHITESPACE@169..170 "\n"
+
+error[syntax-error]: DEFAULT is not allowed in this context
+  ╭▸ 
+1 │ insert into t VALUES (foo(DEFAULT));
+  ╰╴                          ━━━━━━━
+error[syntax-error]: DEFAULT may only assign to a simple column name
+  ╭▸ 
+3 │ UPDATE t SET arr[1] = DEFAULT;
+  ╰╴             ━━━━━━
+error[syntax-error]: DEFAULT may only assign to a simple column name
+  ╭▸ 
+5 │ UPDATE t SET comp.field = DEFAULT;
+  ╰╴             ━━━━━━━━━━
+error[syntax-error]: DEFAULT is not allowed in this context
+  ╭▸ 
+7 │ values (default);
+  ╰╴        ━━━━━━━
+error[syntax-error]: DEFAULT is not allowed in this context
+  ╭▸ 
+9 │ select default;
+  ╰╴       ━━━━━━━
+error[syntax-error]: DEFAULT is not allowed in this context
+   ╭▸ 
+11 │ select 1 where default = 1;
+   ╰╴               ━━━━━━━
diff --git a/crates/squawk_syntax/src/validation.rs b/crates/squawk_syntax/src/validation.rs
index 6aa43ba4..affb9416 100644
--- a/crates/squawk_syntax/src/validation.rs
+++ b/crates/squawk_syntax/src/validation.rs
@@ -6,7 +6,7 @@
 
 use std::ops::Range;
 
-use crate::ast::AstNode;
+use crate::ast::{AstNode, LitKind};
 use crate::unescape::{escape_unicode_esc_str, uescape_char};
 use crate::{SyntaxNode, SyntaxToken, ast, match_ast, syntax_error::SyntaxError};
 use rowan::{TextRange, TextSize};
@@ -29,6 +29,7 @@ pub(crate) fn validate(root: &SyntaxNode, errors: &mut Vec<SyntaxError>) {
                 ast::RuleStmtList(it) => validate_rule_stmt_list(it, errors),
                 ast::Select(it) => validate_select(it, errors),
                 ast::SelectInto(it) => validate_select_into(it, errors),
+                ast::SetSingleColumn(it) => validate_set_single_column(it, errors),
                 ast::SourceFile(it) => validate_source_file(it, errors),
                 _ => (),
             }
@@ -245,6 +246,62 @@ fn validate_literal(lit: ast::Literal, acc: &mut Vec<SyntaxError>) {
 
     validate_unicode_esc_string(&lit, acc);
     validate_prefixed_strings(&lit, acc);
+    validate_default_literal(&lit, acc);
+}
+
+fn validate_default_literal(lit: &ast::Literal, acc: &mut Vec<SyntaxError>) {
+    if !matches!(lit.kind(), Some(LitKind::Default(_))) {
+        return;
+    }
+    let node = lit.syntax();
+    if is_valid_default_literal_position(node) {
+        return;
+    }
+    acc.push(SyntaxError::new(
+        "DEFAULT is not allowed in this context",
+        node.text_range(),
+    ));
+}
+
+fn is_valid_default_literal_position(literal: &SyntaxNode) -> bool {
+    for ancestor in literal.ancestors().skip(1) {
+        match ancestor.kind() {
+            // unwrap parens
+            PAREN_EXPR => continue,
+            SET_EXPR => return true,
+            ROW => return is_row_in_insert_values(&ancestor),
+            _ => return false,
+        }
+    }
+    false
+}
+
+fn is_row_in_insert_values(row: &SyntaxNode) -> bool {
+    // row_list
+    row.parent()
+        // values
+        .and_then(|n| n.parent())
+        // insert / merge_insert
+        .and_then(|n| n.parent())
+        .is_some_and(|p| matches!(p.kind(), INSERT | MERGE_INSERT))
+}
+
+fn validate_set_single_column(it: ast::SetSingleColumn, acc: &mut Vec<SyntaxError>) {
+    let Some(set_expr) = it.set_expr() else {
+        return;
+    };
+    if set_expr.default_token().is_none() {
+        return;
+    }
+    let Some(column) = it.column() else {
+        return;
+    };
+    if column.index_expr().is_some() || column.field_expr().is_some() {
+        acc.push(SyntaxError::new(
+            "DEFAULT may only assign to a simple column name",
+            column.syntax().text_range(),
+        ));
+    }
 }
 
 #[derive(Clone, Copy)]
diff --git a/crates/squawk_syntax/test_data/validation/default.sql b/crates/squawk_syntax/test_data/validation/default.sql
new file mode 100644
index 00000000..4f399b53
--- /dev/null
+++ b/crates/squawk_syntax/test_data/validation/default.sql
@@ -0,0 +1,11 @@
+insert into t VALUES (foo(DEFAULT));
+
+UPDATE t SET arr[1] = DEFAULT;
+
+UPDATE t SET comp.field = DEFAULT;
+
+values (default);
+
+select default;
+
+select 1 where default = 1;
diff --git a/crates/squawk_syntax/test_data/validation/default_ok.sql b/crates/squawk_syntax/test_data/validation/default_ok.sql
new file mode 100644
index 00000000..9fd10e9f
--- /dev/null
+++ b/crates/squawk_syntax/test_data/validation/default_ok.sql
@@ -0,0 +1,25 @@
+UPDATE t SET col = DEFAULT;
+
+UPDATE t SET (a,b) = (DEFAULT, 1);
+
+INSERT into t VALUES (DEFAULT);
+
+MERGE INTO target t
+  USING source s
+     ON t.id = s.id
+  WHEN NOT MATCHED THEN
+      INSERT (id, name, qty) VALUES (s.id, DEFAULT, DEFAULT);
+
+MERGE INTO target t
+  USING source s
+     ON t.id = s.id
+  WHEN MATCHED THEN
+      UPDATE SET qty2 = DEFAULT;
+
+UPDATE t SET col = (DEFAULT);
+
+UPDATE t SET col = (((DEFAULT)));
+
+UPDATE t SET (a, b) = ((DEFAULT), 1);
+
+INSERT INTO t VALUES ((DEFAULT));