Add support for LIKE and NOT LIKE pattern matching commands

sql/analyze_test.go

@@ -202,12 +202,11 @@ func TestSimplifyExpr(t *testing.T) {
 		{`(a, b) = (1, 2) OR (a, b) = (3, 4)`, `(a, b) IN ((1, 2), (3, 4))`},
 		{`(a, b) IN ((2, 1), (1, 2), (1, 2), (2, 1))`, `(a, b) IN ((1, 2), (2, 1))`},
 
-		// TODO(pmattis): unsupported comparison operator: LIKE
-		// {`i LIKE '%foo'`, `true`},
-		// {`i LIKE 'foo'`, `i = 'foo'`},
-		// {`i LIKE 'foo%'`, `i >= 'foo' AND i < 'fop'`},
-		// {`i LIKE 'foo_'`, `i >= 'foo' AND i < 'fop'`},
-		// {`i LIKE 'bar_foo%'`, `i >= 'bar' AND i < 'bas'`},
+		{`i LIKE '%foo'`, `true`},
+		{`i LIKE 'foo'`, `i = 'foo'`},
+		{`i LIKE 'foo%'`, `i >= 'foo' AND i < 'fop'`},
+		{`i LIKE 'foo_'`, `i >= 'foo' AND i < 'fop'`},
+		{`i LIKE 'bar_foo%'`, `i >= 'bar' AND i < 'bas'`},
 		// TODO(pmattis): unsupported comparison operator: SIMILAR TO
 		// {`i SIMILAR TO '.*'`, `true`},
 		// {`i SIMILAR TO 'foo'`, `i = 'foo'`},
@@ -239,9 +238,8 @@ func TestSimplifyNotExpr(t *testing.T) {
 		{`NOT a <= 1`, `a > 1`, true},
 		{`NOT a IN (1, 2)`, `a NOT IN (1, 2)`, true},
 		{`NOT a NOT IN (1, 2)`, `a IN (1, 2)`, true},
-		// TODO(pmattis): unsupported comparison operator: LIKE
-		// {`NOT i LIKE 'foo'`, `true`, false},
-		// {`NOT i NOT LIKE 'foo'`, `i = 'foo'`, false},
+		{`NOT i LIKE 'foo'`, `true`, false},
+		{`NOT i NOT LIKE 'foo'`, `i = 'foo'`, false},
 		// TODO(pmattis): unsupported comparison operator: SIMILAR TO
 		// {`NOT i SIMILAR TO 'foo'`, `true`, false},
 		// {`NOT i NOT SIMILAR TO 'foo'`, `i = 'foo'`, false},

sql/parser/eval.go

@@ -22,7 +22,9 @@ import (
 	"fmt"
 	"math"
 	"reflect"
+	"regexp"
 	"strconv"
+	"strings"
 	"time"
 	"unicode/utf8"
 
@@ -396,6 +398,17 @@ var cmpOps = map[cmpArgs]func(Datum, Datum) (DBool, error){
 	cmpArgs{LE, intervalType, intervalType}: func(left Datum, right Datum) (DBool, error) {
 		return DBool(left.(DInterval).Duration <= right.(DInterval).Duration), nil
 	},
+
+	cmpArgs{Like, stringType, stringType}: func(left Datum, right Datum) (DBool, error) {
+		pattern := regexp.QuoteMeta(string(right.(DString)))
+		pattern = strings.Replace(pattern, "%", ".*", -1)
+		pattern = strings.Replace(pattern, "_", ".", -1)
+		pattern = fmt.Sprintf("^%s$", pattern)
+
+		// TODO(pmattis): Can we cache this regexp compilation?
+		re := regexp.MustCompile(pattern)
+		return DBool(re.MatchString(string(left.(DString)))), nil
+	},
 }
 
 func init() {
@@ -727,6 +740,10 @@ func evalComparisonOp(op ComparisonOp, left, right Datum) (Datum, error) {
 		// NotIn(left, right) is implemented as !IN(left, right)
 		not = true
 		op = In
+	case NotLike:
+		// NotLike(left, right) is implemented as !Like(left, right)
+		not = true
+		op = Like
 	case IsDistinctFrom:
 		// IsDistinctFrom(left, right) is implemented as !EQ(left, right)
 		//
@@ -751,7 +768,7 @@ func evalComparisonOp(op ComparisonOp, left, right Datum) (Datum, error) {
 	}
 
 	switch op {
-	case Like, NotLike, SimilarTo, NotSimilarTo:
+	case SimilarTo, NotSimilarTo:
 		return DNull, util.Errorf("TODO(pmattis): unsupported comparison operator: %s", op)
 	}
 

sql/parser/eval_test.go

@@ -108,6 +108,17 @@ func TestEvalExpr(t *testing.T) {
 		// Comparisons against NULL result in NULL.
 		{`0 = NULL`, `NULL`},
 		{`NULL = NULL`, `NULL`},
+		// LIKE and NOT LIKE
+		{`'TEST' LIKE 'TEST'`, `true`},
+		{`'TEST' LIKE 'TE%'`, `true`},
+		{`'TEST' LIKE '%E%'`, `true`},
+		{`'TEST' LIKE 'TES_'`, `true`},
+		{`'TEST' LIKE 'TE_'`, `false`},
+		{`'TEST' LIKE '%R'`, `false`},
+		{`'TEST' LIKE 'TESTER'`, `false`},
+		{`'TEST' NOT LIKE '%E%'`, `false`},
+		{`'TEST' NOT LIKE 'TES_'`, `false`},
+		{`'TEST' NOT LIKE 'TE_'`, `true`},
 		// IS DISTINCT FROM can be used to compare NULLs "safely".
 		{`0 IS DISTINCT FROM 0`, `false`},
 		{`0 IS DISTINCT FROM 1`, `true`},

sql/parser/type_check.go

@@ -197,6 +197,9 @@ func typeCheckComparisonOp(op ComparisonOp, dummyLeft, dummyRight Datum) (Datum,
 	case NotIn:
 		// NotIn(left, right) is implemented as !IN(left, right)
 		op = In
+	case NotLike:
+		// NotLike(left, right) is implemented as !Like(left, right)
+		op = Like
 	}
 
 	lType := reflect.TypeOf(dummyLeft)
@@ -219,7 +222,7 @@ func typeCheckComparisonOp(op ComparisonOp, dummyLeft, dummyRight Datum) (Datum,
 	}
 
 	switch op {
-	case Like, NotLike, SimilarTo, NotSimilarTo:
+	case SimilarTo, NotSimilarTo:
 		return nil, util.Errorf("TODO(pmattis): unsupported comparison operator: %s", op)
 	}