[Tarantool-patches] [PATCH v2 08/15] sql: rework TOTAL()

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

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

Part of #4145
Part of #6355
---
 src/box/sql/func.c                       | 47 ++++++++++++++++--------
 test/sql-tap/built-in-functions.test.lua | 33 ++++++++++++++++-
 2 files changed, 63 insertions(+), 17 deletions(-)

diff --git a/src/box/sql/func.c b/src/box/sql/func.c
index b06955302..12a6a5a2c 100644
--- a/src/box/sql/func.c
+++ b/src/box/sql/func.c
@@ -76,6 +76,32 @@ fin_sum(struct sql_context *ctx)
 	mem_copy_as_ephemeral(ctx->pOut, ctx->pMem);
 }
 
+/** Implementation of the TOTAL() function. */
+static void
+step_total(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)
+		mem_set_double(ctx->pMem, 0.0);
+	if (mem_add(ctx->pMem, argv[0], ctx->pMem) != 0)
+		ctx->is_aborted = true;
+}
+
+/** Finalizer for the TOTAL() function. */
+static void
+fin_total(struct sql_context *ctx)
+{
+	assert(ctx->pMem->type == MEM_TYPE_NULL || mem_is_double(ctx->pMem));
+	if (ctx->pMem->type == MEM_TYPE_NULL)
+		mem_set_double(ctx->pOut, 0.0);
+	else
+		mem_copy_as_ephemeral(ctx->pOut, ctx->pMem);
+}
+
 static const unsigned char *
 mem_as_ustr(struct Mem *mem)
 {
@@ -1693,17 +1719,6 @@ avgFinalize(sql_context * context)
 		context->is_aborted = true;
 }
 
-static void
-totalFinalize(sql_context * context)
-{
-	SumCtx *p;
-	p = sql_aggregate_context(context, 0);
-	if (p == NULL || p->count == 0)
-		mem_set_double(context->pOut, 0.0);
-	else
-		mem_copy_as_ephemeral(context->pOut, &p->mem);
-}
-
 /*
  * The following structure keeps track of state information for the
  * count() aggregate function.
@@ -2128,10 +2143,12 @@ static struct sql_func_definition definitions[] = {
 	{"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,
-	 totalFinalize},
+	{"TOTAL", 1, {FIELD_TYPE_DOUBLE}, FIELD_TYPE_DOUBLE, step_total,
+	 fin_total},
+	{"TOTAL", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_DOUBLE, step_total,
+	 fin_total},
+	{"TOTAL", 1, {FIELD_TYPE_DECIMAL}, FIELD_TYPE_DOUBLE, step_total,
+	 fin_total},
 
 	{"TRIM", 2, {FIELD_TYPE_STRING, FIELD_TYPE_INTEGER},
 	 FIELD_TYPE_STRING, trim_func, NULL},
diff --git a/test/sql-tap/built-in-functions.test.lua b/test/sql-tap/built-in-functions.test.lua
index 8daf41c1d..507d06549 100755
--- a/test/sql-tap/built-in-functions.test.lua
+++ b/test/sql-tap/built-in-functions.test.lua
@@ -1,6 +1,6 @@
 #!/usr/bin/env tarantool
 local test = require("sqltester")
-test:plan(55)
+test:plan(58)
 
 local dec = require('decimal')
 
@@ -497,7 +497,7 @@ test:do_test(
         local res = {pcall(box.execute, [[SELECT TOTAL(?);]], {'1'})}
         return {tostring(res[3])}
     end, {
-        "Type mismatch: can not convert string('1') to integer"
+        "Type mismatch: can not convert string('1') to double"
     })
 
 --
@@ -576,4 +576,33 @@ test:do_execsql_test(
     }
 )
 
+-- Make sure TOTAL() accepts DOUBLE by default.
+test:do_test(
+    "builtins-4.2.1",
+    function()
+        return box.execute([[SELECT TOTAL(?);]], {1}).metadata
+    end, {
+        {name = "COLUMN_1", type = "double"},
+    })
+
+test:do_test(
+    "builtins-4.2.2",
+    function()
+        local res = {pcall(box.execute, [[SELECT TOTAL(?);]], {-1ULL})}
+        return {tostring(res[3])}
+    end, {
+        "Type mismatch: can not convert integer(18446744073709551615) to double"
+    })
+
+-- Make sure TOTAL() works with DECIMAL properly.
+test:do_execsql_test(
+    "builtins-4.2.3",
+    [[
+        SELECT TOTAL(cast(column_2 as DECIMAL)) from (values(1), (123.432));
+    ]],
+    {
+        124.432
+    }
+)
+
 test:finish_test()
-- 
2.25.1