add UseColums function to avoid extra allocation performed by Colums function

fix name

tidy

adding SetWhere

adding SetWhere

fix go mod

fix comment style

revert go mod

Avoid to append if no needed

fix git ignore

revert change in go.sum/go.mod

adding specific benchmark

.gitignore

@@ -12,3 +12,6 @@
 
 # Go vendor dir
 vendor
+
+# GoLand IDE
+.idea/

qb/select.go

@@ -132,7 +132,11 @@ func (b *SelectBuilder) Json() *SelectBuilder {
 
 // Columns adds result columns to the query.
 func (b *SelectBuilder) Columns(columns ...string) *SelectBuilder {
-	b.columns = append(b.columns, columns...)
+	if len(b.columns) == 0 {
+		b.columns = columns
+	} else {
+		b.columns = append(b.columns, columns...)
+	}
 	return b
 }
 
@@ -143,21 +147,33 @@ func As(column, name string) string {
 
 // Distinct sets DISTINCT clause on the query.
 func (b *SelectBuilder) Distinct(columns ...string) *SelectBuilder {
-	b.distinct = append(b.distinct, columns...)
+	if len(b.where) == 0 {
+		b.distinct = columns
+	} else {
+		b.distinct = append(b.distinct, columns...)
+	}
 	return b
 }
 
 // Where adds an expression to the WHERE clause of the query. Expressions are
 // ANDed together in the generated CQL.
 func (b *SelectBuilder) Where(w ...Cmp) *SelectBuilder {
-	b.where = append(b.where, w...)
+	if len(b.where) == 0 {
+		b.where = w
+	} else {
+		b.where = append(b.where, w...)
+	}
 	return b
 }
 
 // GroupBy sets GROUP BY clause on the query. Columns must be a primary key,
 // this will automatically add the the columns as first selectors.
 func (b *SelectBuilder) GroupBy(columns ...string) *SelectBuilder {
-	b.groupBy = append(b.groupBy, columns...)
+	if len(b.groupBy) == 0 {
+		b.groupBy = columns
+	} else {
+		b.groupBy = append(b.groupBy, columns...)
+	}
 	return b
 }
 

qb/select_bench_test.go

@@ -9,6 +9,23 @@ import "testing"
 func BenchmarkSelectBuilder(b *testing.B) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		Select("cycling.cyclist_name").Columns("id", "user_uuid", "firstname", "stars").Where(Eq("id")).ToCql()
+		Select("cycling.cyclist_name").
+			Columns("id", "user_uuid", "firstname", "surname", "stars").
+			Where(Eq("id")).
+			ToCql()
+	}
+}
+
+func BenchmarkSelectBuildAssign(b *testing.B) {
+	b.ResetTimer()
+	cols := []string{
+		"id", "user_uuid", "firstname",
+		"surname", "stars",
+	}
+	for i := 0; i < b.N; i++ {
+		Select("cycling.cyclist_name").
+			Columns(cols...).
+			Where(Eq("id")).
+			ToCql()
 	}
 }

qb/token.go

@@ -14,7 +14,7 @@ type TokenBuilder []string
 
 // Token creates a new TokenBuilder.
 func Token(columns ...string) TokenBuilder {
-	return TokenBuilder(columns)
+	return columns
 }
 
 // Eq produces token(column)=token(?).

qb/update.go

@@ -212,14 +212,22 @@ func (b *UpdateBuilder) removeValue(column string, value value) *UpdateBuilder {
 // Where adds an expression to the WHERE clause of the query. Expressions are
 // ANDed together in the generated CQL.
 func (b *UpdateBuilder) Where(w ...Cmp) *UpdateBuilder {
-	b.where = append(b.where, w...)
+	if len(b.where) == 0 {
+		b.where = w
+	} else {
+		b.where = append(b.where, w...)
+	}
 	return b
 }
 
 // If adds an expression to the IF clause of the query. Expressions are ANDed
 // together in the generated CQL.
 func (b *UpdateBuilder) If(w ...Cmp) *UpdateBuilder {
-	b._if = append(b._if, w...)
+	if len(b._if) == 0 {
+		b._if = w
+	} else {
+		b._if = append(b._if, w...)
+	}
 	return b
 }