Literal and cast clean up.

mysql/cast.go

@@ -2,14 +2,27 @@ package mysql
 
 import (
 	"github.com/go-jet/jet/internal/jet"
+	"strconv"
 )
 
 type cast interface {
-	jet.Cast
-
+	// Cast expressions as castType type
+	AS(castType string) Expression
+	// Cast expression as char with optional length
+	AS_CHAR(lenght ...int) StringExpression
+	// Cast expression AS date type
+	AS_DATE() DateExpression
+	// Cast expression AS numeric type, using precision and optionally scale
+	AS_DECIMAL() FloatExpression
+	// Cast expression AS time type
+	AS_TIME() TimeExpression
+	// Cast expression as datetime type
 	AS_DATETIME() DateTimeExpression
+	// Cast expressions as signed integer type
 	AS_SIGNED() IntegerExpression
+	// Cast expression as unsigned integer type
 	AS_UNSIGNED() IntegerExpression
+	// Cast expression as binary type
 	AS_BINARY() StringExpression
 }
 
@@ -25,6 +38,10 @@ func CAST(expr jet.Expression) cast {
 	return castImpl
 }
 
+func (c *castImpl) AS(castType string) Expression {
+	return c.Cast.AS(castType)
+}
+
 func (c *castImpl) AS_DATETIME() DateTimeExpression {
 	return DateTimeExp(c.AS("DATETIME"))
 }
@@ -37,6 +54,29 @@ func (c *castImpl) AS_UNSIGNED() IntegerExpression {
 	return IntExp(c.AS("UNSIGNED"))
 }
 
+func (b *castImpl) AS_CHAR(lenght ...int) StringExpression {
+	if len(lenght) > 0 {
+		return StringExp(b.AS("CHAR(" + strconv.Itoa(lenght[0]) + ")"))
+	}
+
+	return StringExp(b.AS("CHAR"))
+}
+
+// Cast expression AS date type
+func (b *castImpl) AS_DATE() DateExpression {
+	return DateExp(b.AS("DATE"))
+}
+
+// Cast expression AS date type
+func (b *castImpl) AS_DECIMAL() FloatExpression {
+	return FloatExp(b.AS("DECIMAL"))
+}
+
+// Cast expression AS date type
+func (b *castImpl) AS_TIME() TimeExpression {
+	return TimeExp(b.AS("TIME"))
+}
+
 func (c *castImpl) AS_BINARY() StringExpression {
 	return StringExp(c.AS("BINARY"))
 }