querying within json

<div dir="ltr">Any advice on how to best query for values within json (using 9.4). I have numeric fields within the
jsonand want to include terms for those fields.<br /><br /> I've found that something like this works:<br /><br />
select* from atable where (json_col->>'numeric_prop')::numeric < 100;<br /><br /> But whilst that works:<br />
1.seems to have unnecessary casts? The numeric _prop item is of numeric type, but its getting retrieved as text and
thencast to numeric and then compared<br /> 2. its not going to use any index on the json_col jsonb column.<br /><br />
Isthere a better way to do this?<br /><br /><br /> Thanks<br /> Tim<br /></div>