Support using field regex comparisons in the WHERE clause

Fixes #2715.

CHANGELOG.md

@@ -21,6 +21,7 @@
 - [#5844](https://github.com/influxdata/influxdb/pull/5844): Tag TSM engine stats with database and retention policy
 - [#5593](https://github.com/influxdata/influxdb/issues/5593): Modify `SHOW TAG VALUES` output for the new query engine to normalize the output.
 - [#5862](https://github.com/influxdata/influxdb/pull/5862): Make Admin UI dynamically fetch both client and server versions
+- [#2715](https://github.com/influxdata/influxdb/issues/2715): Support using field regex comparisons in the WHERE clause
 
 ### Bugfixes
 

influxql/ast.go

@@ -3485,6 +3485,8 @@ func Eval(expr Expr, m map[string]interface{}) interface{} {
 		return expr.Val
 	case *ParenExpr:
 		return Eval(expr.Expr, m)
+	case *RegexLiteral:
+		return expr.Val
 	case *StringLiteral:
 		return expr.Val
 	case *VarRef:
@@ -3570,12 +3572,19 @@ func evalBinaryExpr(expr *BinaryExpr, m map[string]interface{}) interface{} {
 			return lhs / rhs
 		}
 	case string:
-		rhs, _ := rhs.(string)
 		switch expr.Op {
 		case EQ:
-			return lhs == rhs
+			rhs, ok := rhs.(string)
+			return ok && lhs == rhs
 		case NEQ:
-			return lhs != rhs
+			rhs, ok := rhs.(string)
+			return ok && lhs != rhs
+		case EQREGEX:
+			rhs, ok := rhs.(*regexp.Regexp)
+			return ok && rhs.MatchString(lhs)
+		case NEQREGEX:
+			rhs, ok := rhs.(*regexp.Regexp)
+			return ok && !rhs.MatchString(lhs)
 		}
 	}
 	return nil

influxql/ast_test.go

@@ -1014,11 +1014,19 @@ func TestEval(t *testing.T) {
 		{in: `'foo' = 'bar'`, out: false},
 		{in: `'foo' = 'foo'`, out: true},
 
+		// Regex literals.
+		{in: `'foo' =~ /f.*/`, out: true},
+		{in: `'foo' =~ /b.*/`, out: false},
+		{in: `'foo' !~ /f.*/`, out: false},
+		{in: `'foo' !~ /b.*/`, out: true},
+
 		// Variable references.
 		{in: `foo`, out: "bar", data: map[string]interface{}{"foo": "bar"}},
 		{in: `foo = 'bar'`, out: true, data: map[string]interface{}{"foo": "bar"}},
 		{in: `foo = 'bar'`, out: nil, data: map[string]interface{}{"foo": nil}},
 		{in: `foo <> 'bar'`, out: true, data: map[string]interface{}{"foo": "xxx"}},
+		{in: `foo =~ /b.*/`, out: true, data: map[string]interface{}{"foo": "bar"}},
+		{in: `foo !~ /b.*/`, out: false, data: map[string]interface{}{"foo": "bar"}},
 	} {
 		// Evaluate expression.
 		out := influxql.Eval(MustParseExpr(tt.in), tt.data)