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| author |  Adam Chlipala <adam@chlipala.net> | 2018-03-13 15:30:11 -0400 |
|---|---|---|
| committer | Adam Chlipala <adam@chlipala.net> | 2018-03-13 15:30:11 -0400 |
| commit | de2d8358dda08bfaf491d815df91d0c1ba33e7c9 (patch) | |
| tree | f819be05586e191199befbcbf87b5743e3cdcc9c | |
| parent | e2d548c69e2a83ace5123ade21262aa27336fb6b (diff) | |
Handle empty SELECT clauses
| -rw-r--r-- | src/monoize.sml | 27 | ||||
| -rw-r--r-- | src/postgres.sml | 11 |
2 files changed, 24 insertions, 14 deletions
diff --git a/src/monoize.sml b/src/monoize.sml index 60ff78ea..85a66e87 100644 --- a/src/monoize.sml +++ b/src/monoize.sml @@ -1792,18 +1792,21 @@ fun monoExp (env, st, fm) (all as (e, loc)) = NONE), loc), str "")], {disc = b, result = s}), loc), - strcatComma (map (fn (x, t) => - strcat [ - (L'.EField (gf "SelectExps", x), loc), - str (" AS " ^ Settings.mangleSql x) - ]) sexps - @ map (fn (x, xts) => - strcatComma - (map (fn (x', _) => - str ("T_" ^ x - ^ "." - ^ Settings.mangleSql x')) - xts)) stables), + if List.null sexps andalso List.all (List.null o #2) stables then + str "0" + else + strcatComma (map (fn (x, t) => + strcat [ + (L'.EField (gf "SelectExps", x), loc), + str (" AS " ^ Settings.mangleSql x) + ]) sexps + @ map (fn (x, xts) => + strcatComma + (map (fn (x', _) => + str ("T_" ^ x + ^ "." + ^ Settings.mangleSql x')) + xts)) stables), (L'.ECase (gf "From", [((L'.PPrim (Prim.String (Prim.Normal, "")), loc), str ""), diff --git a/src/postgres.sml b/src/postgres.sml index 404384d2..fac913f0 100644 --- a/src/postgres.sml +++ b/src/postgres.sml @@ -612,6 +612,13 @@ fun p_getcol {loc, wontLeakStrings, col = i, typ = t} = getter t end +(* We turn 0-output queries into 1-output queries to satisfy SQL. + * This function adjusts our length expectations. *) +fun bumpedLength ls = + case ls of + [] => 1 + | _ => length ls + fun queryCommon {loc, query, cols, doCols} = box [string "int n, i;", newline, @@ -658,7 +665,7 @@ fun queryCommon {loc, query, cols, doCols} = newline, string "if (PQnfields(res) != ", - string (Int.toString (length cols)), + string (Int.toString (bumpedLength cols)), string ") {", newline, box [string "int nf = PQnfields(res);", @@ -668,7 +675,7 @@ fun queryCommon {loc, query, cols, doCols} = string "uw_error(ctx, FATAL, \"", string (ErrorMsg.spanToString loc), string ": Query returned %d columns instead of ", - string (Int.toString (length cols)), + string (Int.toString (bumpedLength cols)), string ":\\n%s\\n%s\", nf, ", query, string ", PQerrorMessage(conn));", |