diff --git a/mysql_client.lua b/mysql_client.lua
index 9a9fb1c..eb349ab 100644
--- a/mysql_client.lua
+++ b/mysql_client.lua
@@ -21,6 +21,8 @@ local shl = bit.lshift
 local shr = bit.rshift
 local tohex = bit.tohex
 local concat = table.concat
+local floor = math.floor
+local tonumber = tonumber
 
 local buffer = glue.buffer
 local dynarray = glue.dynarray
@@ -599,9 +601,9 @@ local function get_time(buf, time_format)
 	end
 	local sign = get_u8(buf) == 1 and -1 or 1
 	local days = get_u4(buf) * sign
-	local H = get_u8(buf)
-	local M = get_u8(buf)
-	local S = get_u8(buf)
+	local H    = get_u8(buf)
+	local M    = get_u8(buf)
+	local S    = get_u8(buf)
 	local ms = len == 8 and 0 or get_u32(buf)
 	return time_format == '*t'
 		and {days = days, hour = H, min = M, sec = S + ms / 10^6}
@@ -612,11 +614,59 @@ local function get_time(buf, time_format)
 end
 
 local function set_datetime(buf, t)
-
+	local y, m, d, H, M, S
+	if type(t) == 'string' then
+		y, m, d, t = t:match'^(%d+)-(%d+)-(%d+)(.*)'
+		H, M, S = t:match' (%d+):(%d+):([%d.]+)'
+		y = tonumber(y)
+		m = tonumber(m)
+		d = tonumber(d)
+		H = tonumber(H) or 0
+		M = tonumber(M) or 0
+		S = tonumber(S) or 0
+	else
+		y = t.year
+		m = t.month
+		d = t.day
+		H = t.hour
+		M = t.min
+		S = t.sec
+	end
+	local ms = (S - floor(S)) * 10^6
+	set_u8 (buf, 11)
+	set_u16(buf, y)
+	set_u8 (buf, m)
+	set_u8 (buf, d)
+	set_u8 (buf, H)
+	set_u8 (buf, M)
+	set_u8 (buf, S)
+	set_u32(buf, ms)
 end
 
 local function set_time(buf, t)
-
+	local days, H, M, S
+	if type(t) == 'string' then
+		local d, rest = t:match'^([+%-%d]+)d (.*)'
+		days = d and tonumber(d) or 0
+		t = d and rest or t
+		H, M, S = t:match'^(%d+):(%d+):([%d.]+)$'
+		H = tonumber(H)
+		M = tonumber(M)
+		S = tonumber(S)
+	else
+		days = (t.days or 0) + floor(t.hour / 24)
+		H = t.hour % 24
+		M = t.min
+		S = t.sec
+	end
+	local ms = (S - floor(S)) * 10^6
+	set_u8 (buf, 12)
+	set_u8 (buf, days < 0 and 1 or 0)
+	set_u32(buf, math.abs(days))
+	set_u8 (buf, H)
+	set_u8 (buf, M)
+	set_u8 (buf, S)
+	set_u32(buf, ms)
 end
 
 local function set_u8(buf, x)
@@ -1006,7 +1056,7 @@ function conn:read_result(opt)
 
 		if self.state == 'read_binary' then
 			check(get_u8(buf) == 0, 'invalid row packet')
-			local nulls_len = math.floor((#cols + 7 + 2) / 8)
+			local nulls_len = floor((#cols + 7 + 2) / 8)
 			local nulls, nulls_offset = buf(nulls_len)
 			for i, col in ipairs(cols) do
 				local null_byte = shr(i-1+2, 3) + nulls_offset
@@ -1141,7 +1191,7 @@ function stmt:exec(...)
 	set_u8(buf, stmt.cursor)
 	set_u32(buf, 1) --iteration-count, must be 1
 	if #stmt.params > 0 then
-		local nulls_len = math.floor((#stmt.params + 7) / 8)
+		local nulls_len = floor((#stmt.params + 7) / 8)
 		local nulls = ffi.new('uint8_t[?]', nulls_len)
 		for i = 1, #stmt.params do
 			local val = select(i, ...)