From d74adcbb159280be962918125d20ec8ac67a3f93 Mon Sep 17 00:00:00 2001
From: xuri <xuri.me@gmail.com>
Date: Sun, 3 Jul 2022 15:31:24 +0800
Subject: [PATCH] ref #65, new formula function: DGET

---
 calc.go      | 27 +++++++++++++++++++++++++++
 calc_test.go |  4 ++++
 2 files changed, 31 insertions(+)

diff --git a/calc.go b/calc.go
index 25c2e180..83885dc6 100644
--- a/calc.go
+++ b/calc.go
@@ -433,6 +433,7 @@ type formulaFuncs struct {
 //    DEGREES
 //    DELTA
 //    DEVSQ
+//    DGET
 //    DISC
 //    DMAX
 //    DMIN
@@ -18173,6 +18174,32 @@ func (fn *formulaFuncs) DCOUNTA(argsList *list.List) formulaArg {
 	return fn.dcount("DCOUNTA", argsList)
 }
 
+// DGET function returns a single value from a column of a database. The record
+// is selected via a set of one or more user-specified criteria. The syntax of
+// the function is:
+//
+//    DGET(database,field,criteria)
+//
+func (fn *formulaFuncs) DGET(argsList *list.List) formulaArg {
+	if argsList.Len() != 3 {
+		return newErrorFormulaArg(formulaErrorVALUE, "DGET requires 3 arguments")
+	}
+	database := argsList.Front().Value.(formulaArg)
+	field := argsList.Front().Next().Value.(formulaArg)
+	criteria := argsList.Back().Value.(formulaArg)
+	db := newCalcDatabase(database, field, criteria)
+	if db == nil {
+		return newErrorFormulaArg(formulaErrorVALUE, formulaErrorVALUE)
+	}
+	value := newErrorFormulaArg(formulaErrorVALUE, formulaErrorVALUE)
+	if db.next() {
+		if value = db.value(); db.next() {
+			return newErrorFormulaArg(formulaErrorNUM, formulaErrorNUM)
+		}
+	}
+	return value
+}
+
 // DMAX function finds the maximum value in a field (column) in a database for
 // selected records only. The records to be included in the calculation are
 // defined by a set of one or more user-specified criteria. The syntax of the
diff --git a/calc_test.go b/calc_test.go
index 4436b608..b8efd619 100644
--- a/calc_test.go
+++ b/calc_test.go
@@ -4632,6 +4632,7 @@ func TestCalcDatabase(t *testing.T) {
 		"=DCOUNTA(A4:E10,\"Profit\",A1:F2)":  "2",
 		"=DCOUNTA(A4:E10,\"Tree\",A1:F2)":    "2",
 		"=DCOUNTA(A4:E10,\"Age\",A2:F3)":     "0",
+		"=DGET(A4:E6,\"Profit\",A1:F3)":      "96",
 		"=DMAX(A4:E10,\"Tree\",A1:F3)":       "0",
 		"=DMAX(A4:E10,\"Profit\",A1:F3)":     "96",
 		"=DMIN(A4:E10,\"Tree\",A1:F3)":       "0",
@@ -4665,6 +4666,9 @@ func TestCalcDatabase(t *testing.T) {
 		"=DCOUNTA(A4:E10,NA(),A1:F2)":         "#VALUE!",
 		"=DCOUNTA(A4:E4,,A1:F2)":              "#VALUE!",
 		"=DCOUNTA(A4:E10,\"x\",A2:F3)":        "#VALUE!",
+		"=DGET()":                             "DGET requires 3 arguments",
+		"=DGET(A4:E5,\"Profit\",A1:F3)":       "#VALUE!",
+		"=DGET(A4:E10,\"Profit\",A1:F3)":      "#NUM!",
 		"=DMAX()":                             "DMAX requires 3 arguments",
 		"=DMAX(A4:E10,\"x\",A1:F3)":           "#VALUE!",
 		"=DMIN()":                             "DMIN requires 3 arguments",