fb-1809: SQL3 RTrim & LTrim func for strings (#2361)

sql3/planner/expression.go

@@ -1492,6 +1492,10 @@ func (n *callPlanExpression) Evaluate(currentRow []interface{}) (interface{}, er
 		return n.EvaluateReplaceAll(currentRow)
 	case "TRIM":
 		return n.EvaluateTrim(currentRow)
+	case "RTRIM":
+		return n.EvaluateRTrim(currentRow)
+	case "LTRIM":
+		return n.EvaluateLTrim(currentRow)
 	default:
 		return nil, sql3.NewErrInternalf("unhandled function name '%s'", n.name)
 	}

sql3/planner/expressionanalyzercall.go

@@ -253,6 +253,10 @@ func (p *ExecutionPlanner) analyzeCallExpression(call *parser.Call, scope parser
 		return p.analyseFunctionReplaceAll(call, scope)
 	case "TRIM":
 		return p.analyseFunctionTrim(call, scope)
+	case "RTRIM":
+		return p.analyseFunctionTrim(call, scope)
+	case "LTRIM":
+		return p.analyseFunctionTrim(call, scope)
 
 	default:
 		return nil, sql3.NewErrCallUnknownFunction(call.Name.NamePos.Line, call.Name.NamePos.Column, call.Name.Name)

sql3/planner/inbuiltfunctionsstring.go

@@ -201,9 +201,9 @@ func evaluateStringArg(n types.PlanExpression, currentRow []interface{}) (string
 	return stringArgOne, nil
 }
 
-// Analyze function for Trim
+// Analyze function for Trim/RTrim/LTrim
 func (p *ExecutionPlanner) analyseFunctionTrim(call *parser.Call, scope parser.Statement) (parser.Expr, error) {
-	//one argument for Trim Function
+	//one argument for Trim Functions
 	if len(call.Args) != 1 {
 		return nil, sql3.NewErrCallParameterCountMismatch(call.Rparen.Line, call.Rparen.Column, call.Name.Name, 1, len(call.Args))
 	}
@@ -227,3 +227,25 @@ func (n *callPlanExpression) EvaluateTrim(currentRow []interface{}) (interface{}
 	// Trim the whitespace from string
 	return strings.TrimSpace(stringArgOne), nil
 }
+
+// Execute RTrim function to remove trailing whitespaces from string
+func (n *callPlanExpression) EvaluateRTrim(currentRow []interface{}) (interface{}, error) {
+	stringArgOne, err := evaluateStringArg(n.args[0], currentRow)
+	if err != nil {
+		return nil, err
+	}
+
+	// Trim the trailing whitespace from string
+	return strings.TrimRight(stringArgOne, " "), nil
+}
+
+// Execute LTrim function to remove leading whitespaces from string
+func (n *callPlanExpression) EvaluateLTrim(currentRow []interface{}) (interface{}, error) {
+	stringArgOne, err := evaluateStringArg(n.args[0], currentRow)
+	if err != nil {
+		return nil, err
+	}
+
+	// Trim the leading whitespace from string
+	return strings.TrimLeft(stringArgOne, " "), nil
+}

sql3/test/defs/defs_string_functions.go

@@ -242,5 +242,59 @@ var stringScalarFunctionsTests = TableTest{
 			),
 			ExpErr: "string expression expected",
 		},
+		{
+			name: "RemovingTrailingspacefromStringusingRTrim",
+			SQLs: sqls(
+				"select rtrim('  this  ')",
+			),
+			ExpHdrs: hdrs(
+				hdr("", fldTypeString),
+			),
+			ExpRows: rows(
+				row(string("  this")),
+			),
+			Compare: CompareExactOrdered,
+		},
+		{
+			name: "IncorrectArgumentsforRTrim",
+			SQLs: sqls(
+				"select rtrim(' a ',' b ')",
+			),
+			ExpErr: "'rtrim': count of formal parameters (1) does not match count of actual parameters (2)",
+		},
+		{
+			name: "IncorrectInputforRTrim",
+			SQLs: sqls(
+				"select rtrim(1)",
+			),
+			ExpErr: "string expression expected",
+		},
+		{
+			name: "RemovingLeadingspacefromStringusingLTrim",
+			SQLs: sqls(
+				"select ltrim('  this  ')",
+			),
+			ExpHdrs: hdrs(
+				hdr("", fldTypeString),
+			),
+			ExpRows: rows(
+				row(string("this  ")),
+			),
+			Compare: CompareExactOrdered,
+		},
+		{
+			name: "IncorrectArgumentsforLTrim",
+			SQLs: sqls(
+				"select ltrim(' a ',' b ')",
+			),
+			ExpErr: "'ltrim': count of formal parameters (1) does not match count of actual parameters (2)",
+		},
+		{
+			name: "IncorrectInputforLTrim",
+			SQLs: sqls(
+				"select ltrim(1)",
+			),
+			ExpErr: "string expression expected",
+		},
 	},
 }