support expr

[liyongjing]

I want add basic expr such as NotEq, NotLike,Lt,LtOrEq,Gt, GtOrEq etc
one api definition such as

func WhereLike(col string, val interface{}) Option{}
func WhereEq(col string, val interface{}) Option {}
func WhereNotEq(col string, val interface{}) Option {}

one api defintion such as

const (
	OpEq   = "="
	OpGt   = ">"
	OpGtOrEq = ">="
	OpLt   = "<"
	OpLike = "LIKE"
)
func Where(col string, op string, val interface{}) Option {}

which?

[andrewpillar]

const ( OpEq = "=" OpGt = ">" OpGtOrEq = ">=" OpLt = "<" OpLike = "LIKE" ) func Where(col string, op string, val interface{}) Option {}

How would this work for WHERE clauses that use "IN"?

[liyongjing]

Which is better for public api defintion? internal implement separately with basic operators and complexity operators.

[andrewpillar]

Which is better for public api defintion?

How about implement the new API, but keep the old public API just as a wrapper around the new one. Something like this: ``` type Op string const ( OpEq Op = "=" ) func Where(col string, op Op, val interface{}) Option {} func WhereEq(col string, val interface{}) Option { return Where(col, OpEq, val) } ``` Also, how about making the `op` passed to the `Where` function its own type? I prefer the explicitness that comes with this. We could also add another function called `WhereRaw` for handling values for the query we don't want to use bindvars for. ``` func WhereRaw(col string, op Op, val interface{}) Option {} ```