Macro sql

sql!() { /* proc-macro */ }

The sql! macro is used to construct a diesel::SqlLiteral<T> using a format string to describe the SQL snippet with the following syntax:

sql!(as T, "format", binds,*)

T is the SqlType that the literal will be interpreted as, as a Rust expression. The format string introduces binders with curly braces, surrounding the SqlType of the bound value. This type is given as a string which must correspond to a type in the diesel::sql_types module. Bound values following in the order matching their binders in the string:

sql!(as Bool, "{BigInt} <= foo AND foo < {BigInt}", 5, 10)

The above macro invocation will generate the following code:

sql::<Bool>("")
   .bind::<BigInt, _>(5)
   .sql(" <= foo AND foo < ")
   .bind::<BigInt, _>(10)
   .sql("")