Description

In our online sqls, there are many nested functions calls, such as

• select a.b.c from test_tbl => select get_struct_field((get_struct_field(a, b),c) from test_tbl
• select count(1) from test_tbl where a = 1 and b = 2 and c = 3 => select count(1) from test_tbl where and(and(a = 1, b = 2), c = 3 )
• select count(1) from test_tbl where a = 1 or b = 2 or c = 3 => select count(1) from test_tbl where or(or(a = 1, b = 2), c = 3 )
  .....

and these functions can be optimized by make the nested arguments collapsed , which means
get_struct_field((get_struct_field(a, b),c) => get_struct_field(a, b, c)
and(and(a = 1, b = 2), c = 3 ) => and(a =1, b=2, c=3)
or(or(a=1, b= 2), c=3) => or(a=1, b=2, c=3)
.....

which can reduce the function calls and improve performance.