[Tarantool-patches] [PATCH v1 06/13] sql: rework SUM()

[Mergen Imeev via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

This patch makes SUM() accept DOUBLE values by default. Also, after this
patch SUM() will be able to work with DECIMAL values.

Part of #4145
Part of #6355
---
 src/box/sql/func.c                       | 39 ++++++++++++++++--------
 src/box/sql/vdbe.c                       |  1 -
 test/sql-tap/built-in-functions.test.lua | 35 +++++++++++++++++++--
 3 files changed, 59 insertions(+), 16 deletions(-)

diff --git a/src/box/sql/func.c b/src/box/sql/func.c
index b4461c6ee..b06955302 100644
--- a/src/box/sql/func.c
+++ b/src/box/sql/func.c
@@ -53,6 +53,29 @@
 static struct mh_strnptr_t *built_in_functions = NULL;
 static struct func_sql_builtin **functions;
 
+/** Implementation of the SUM() function. */
+static void
+step_sum(struct sql_context *ctx, int argc, struct Mem **argv)
+{
+	assert(argc == 1);
+	(void)argc;
+	assert(ctx->pMem->type == MEM_TYPE_NULL || mem_is_num(ctx->pMem));
+	if (argv[0]->type == MEM_TYPE_NULL)
+		return;
+	if (ctx->pMem->type == MEM_TYPE_NULL)
+		return mem_copy_as_ephemeral(ctx->pMem, argv[0]);
+	if (mem_add(ctx->pMem, argv[0], ctx->pMem) != 0)
+		ctx->is_aborted = true;
+}
+
+/** Finalizer for the SUM() function. */
+static void
+fin_sum(struct sql_context *ctx)
+{
+	assert(ctx->pMem->type == MEM_TYPE_NULL || mem_is_num(ctx->pMem));
+	mem_copy_as_ephemeral(ctx->pOut, ctx->pMem);
+}
+
 static const unsigned char *
 mem_as_ustr(struct Mem *mem)
 {
@@ -1654,17 +1677,6 @@ sum_step(struct sql_context *context, int argc, sql_value **argv)
 		context->is_aborted = true;
 }
 
-static void
-sumFinalize(sql_context * context)
-{
-	SumCtx *p;
-	p = sql_aggregate_context(context, 0);
-	if (p == NULL || p->count == 0)
-		mem_set_null(context->pOut);
-	else
-		mem_copy_as_ephemeral(context->pOut, &p->mem);
-}
-
 static void
 avgFinalize(sql_context * context)
 {
@@ -2113,8 +2125,9 @@ static struct sql_func_definition definitions[] = {
 	{"SUBSTR", 3,
 	 {FIELD_TYPE_VARBINARY, FIELD_TYPE_INTEGER, FIELD_TYPE_INTEGER},
 	 FIELD_TYPE_VARBINARY, substrFunc, NULL},
-	{"SUM", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_INTEGER, sum_step, sumFinalize},
-	{"SUM", 1, {FIELD_TYPE_DOUBLE}, FIELD_TYPE_DOUBLE, sum_step, sumFinalize},
+	{"SUM", 1, {FIELD_TYPE_DOUBLE}, FIELD_TYPE_DOUBLE, step_sum, fin_sum},
+	{"SUM", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_INTEGER, step_sum, fin_sum},
+	{"SUM", 1, {FIELD_TYPE_DECIMAL}, FIELD_TYPE_DECIMAL, step_sum, fin_sum},
 	{"TOTAL", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_DOUBLE, sum_step,
 	 totalFinalize},
 	{"TOTAL", 1, {FIELD_TYPE_DOUBLE}, FIELD_TYPE_DOUBLE, sum_step,
diff --git a/src/box/sql/vdbe.c b/src/box/sql/vdbe.c
index dfab86c50..a74ee29ea 100644
--- a/src/box/sql/vdbe.c
+++ b/src/box/sql/vdbe.c
@@ -4207,7 +4207,6 @@ case OP_AggFinal: {
 	assert(pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor));
 	struct func_sql_builtin *func = (struct func_sql_builtin *)pOp->p4.func;
 	struct Mem *pIn1 = &aMem[pOp->p1];
-	assert(mem_is_null(pIn1) || mem_is_agg(pIn1));
 
 	struct sql_context ctx;
 	memset(&ctx, 0, sizeof(ctx));
diff --git a/test/sql-tap/built-in-functions.test.lua b/test/sql-tap/built-in-functions.test.lua
index 6fae811dc..8daf41c1d 100755
--- a/test/sql-tap/built-in-functions.test.lua
+++ b/test/sql-tap/built-in-functions.test.lua
@@ -1,6 +1,8 @@
 #!/usr/bin/env tarantool
 local test = require("sqltester")
-test:plan(52)
+test:plan(55)
+
+local dec = require('decimal')
 
 --
 -- Make sure that number of arguments check is checked properly for SQL built-in
@@ -455,7 +457,7 @@ test:do_test(
         local res = {pcall(box.execute, [[SELECT SUM(?);]], {'1'})}
         return {tostring(res[3])}
     end, {
-        "Type mismatch: can not convert string('1') to integer"
+        "Type mismatch: can not convert string('1') to double"
     })
 
 test:do_catchsql_test(
@@ -545,4 +547,33 @@ test:do_test(
         {name = "COLUMN_2", type = "scalar"},
     })
 
+-- Make sure SUM() accepts and returns DOUBLE by default.
+test:do_test(
+    "builtins-4.1.1",
+    function()
+        return box.execute([[SELECT SUM(?);]], {1}).metadata
+    end, {
+        {name = "COLUMN_1", type = "double"},
+    })
+
+test:do_test(
+    "builtins-4.1.2",
+    function()
+        local res = {pcall(box.execute, [[SELECT SUM(?);]], {-1ULL})}
+        return {tostring(res[3])}
+    end, {
+        "Type mismatch: can not convert integer(18446744073709551615) to double"
+    })
+
+-- Make sure SUM() works with DECIMAL properly.
+test:do_execsql_test(
+    "builtins-4.1.3",
+    [[
+        SELECT SUM(cast(column_2 as DECIMAL)) from (values(1), (123.432));
+    ]],
+    {
+        dec.new(124.432)
+    }
+)
+
 test:finish_test()
-- 
2.25.1