Change the order of parameters in DECODE_HISTOGRAM to match the order of fields in

mysql.column_stats.

mysql-test/r/statistics.result

@@ -1456,7 +1456,7 @@ set histogram_size=254;
 set histogram_type='DOUBLE_PREC_HB';
 ANALYZE TABLE City;
 FLUSH TABLES;
-select UPPER(db_name),UPPER(table_name),UPPER(column_name),min_value,max_value,nulls_ratio,avg_length,avg_frequency,hist_size,hist_type,hex(histogram),decode_histogram(histogram,hist_type) from mysql.column_stats where UPPER(db_name)='WORLD' and UPPER(table_name)='COUNTRYLANGUAGE' and UPPER(column_name) = 'PERCENTAGE';;
+select UPPER(db_name),UPPER(table_name),UPPER(column_name),min_value,max_value,nulls_ratio,avg_length,avg_frequency,hist_size,hist_type,hex(histogram),decode_histogram(hist_type,histogram) from mysql.column_stats where UPPER(db_name)='WORLD' and UPPER(table_name)='COUNTRYLANGUAGE' and UPPER(column_name) = 'PERCENTAGE';;
 UPPER(db_name)	WORLD
 UPPER(table_name)	COUNTRYLANGUAGE
 UPPER(column_name)	PERCENTAGE
@@ -1468,8 +1468,8 @@ avg_frequency	2.7640
 hist_size	100
 hist_type	SINGLE_PREC_HB
 hex(histogram)	0000000000000000000000000101010101010101010202020303030304040404050505050606070707080809090A0A0B0C0D0D0E0E0F10111213131415161718191B1C1E202224292A2E33373B4850575F6A76818C9AA7B9C4CFDADFE5EBF0F4F8FAFCFF
-decode_histogram(histogram,hist_type)	0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.004,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.004,0.000,0.000,0.004,0.000,0.000,0.000,0.004,0.000,0.000,0.000,0.004,0.000,0.000,0.000,0.004,0.000,0.004,0.000,0.000,0.004,0.000,0.004,0.000,0.004,0.000,0.004,0.004,0.004,0.000,0.004,0.000,0.004,0.004,0.004,0.004,0.004,0.000,0.004,0.004,0.004,0.004,0.004,0.004,0.008,0.004,0.008,0.008,0.008,0.008,0.020,0.004,0.016,0.020,0.016,0.016,0.051,0.031,0.027,0.031,0.043,0.047,0.043,0.043,0.055,0.051,0.071,0.043,0.043,0.043,0.020,0.024,0.024,0.020,0.016,0.016,0.008,0.008,0.012,0.000
-select UPPER(db_name),UPPER(table_name),UPPER(column_name),min_value,max_value,nulls_ratio,avg_length,avg_frequency,hist_size,hist_type,hex(histogram),decode_histogram(histogram,hist_type) from mysql.column_stats where UPPER(db_name)='WORLD' and UPPER(table_name)='CITY' and UPPER(column_name) = 'POPULATION';;
+decode_histogram(hist_type,histogram)	0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.004,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.004,0.000,0.000,0.004,0.000,0.000,0.000,0.004,0.000,0.000,0.000,0.004,0.000,0.000,0.000,0.004,0.000,0.004,0.000,0.000,0.004,0.000,0.004,0.000,0.004,0.000,0.004,0.004,0.004,0.000,0.004,0.000,0.004,0.004,0.004,0.004,0.004,0.000,0.004,0.004,0.004,0.004,0.004,0.004,0.008,0.004,0.008,0.008,0.008,0.008,0.020,0.004,0.016,0.020,0.016,0.016,0.051,0.031,0.027,0.031,0.043,0.047,0.043,0.043,0.055,0.051,0.071,0.043,0.043,0.043,0.020,0.024,0.024,0.020,0.016,0.016,0.008,0.008,0.012,0.000
+select UPPER(db_name),UPPER(table_name),UPPER(column_name),min_value,max_value,nulls_ratio,avg_length,avg_frequency,hist_size,hist_type,hex(histogram),decode_histogram(hist_type,histogram) from mysql.column_stats where UPPER(db_name)='WORLD' and UPPER(table_name)='CITY' and UPPER(column_name) = 'POPULATION';;
 UPPER(db_name)	WORLD
 UPPER(table_name)	CITY
 UPPER(column_name)	POPULATION
@@ -1481,7 +1481,7 @@ avg_frequency	1.0467
 hist_size	254
 hist_type	DOUBLE_PREC_HB
 hex(histogram)	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
-decode_histogram(histogram,hist_type)	0.00047,0.00198,0.00601,0.00008,0.00008,0.00005,0.00011,0.00006,0.00009,0.00008,0.00006,0.00009,0.00008,0.00009,0.00008,0.00009,0.00006,0.00006,0.00008,0.00008,0.00008,0.00011,0.00009,0.00008,0.00009,0.00006,0.00011,0.00006,0.00012,0.00012,0.00012,0.00012,0.00011,0.00011,0.00014,0.00011,0.00011,0.00011,0.00014,0.00006,0.00011,0.00009,0.00011,0.00009,0.00015,0.00015,0.00015,0.00009,0.00018,0.00015,0.00015,0.00015,0.00017,0.00018,0.00018,0.00015,0.00018,0.00020,0.00024,0.00021,0.00023,0.00027,0.00024,0.00024,0.00027,0.00023,0.00020,0.00029,0.00020,0.00027,0.00020,0.00027,0.00026,0.00034,0.00024,0.00034,0.00031,0.00037,0.00043,0.00038,0.00038,0.00035,0.00047,0.00056,0.00058,0.00041,0.00047,0.00056,0.00072,0.00044,0.00060,0.00072,0.00061,0.00072,0.00066,0.00085,0.00075,0.00078,0.00082,0.00073,0.00108,0.00089,0.00105,0.00105,0.00151,0.00150,0.00110,0.00145,0.00163,0.00160,0.00165,0.00232,0.00201,0.00371,0.00365,0.00383,0.00459,0.00583,0.00662,0.00984,0.00969,0.01080,0.01379,0.02063,0.04308,0.05960,0.15816,0.59464
+decode_histogram(hist_type,histogram)	0.00047,0.00198,0.00601,0.00008,0.00008,0.00005,0.00011,0.00006,0.00009,0.00008,0.00006,0.00009,0.00008,0.00009,0.00008,0.00009,0.00006,0.00006,0.00008,0.00008,0.00008,0.00011,0.00009,0.00008,0.00009,0.00006,0.00011,0.00006,0.00012,0.00012,0.00012,0.00012,0.00011,0.00011,0.00014,0.00011,0.00011,0.00011,0.00014,0.00006,0.00011,0.00009,0.00011,0.00009,0.00015,0.00015,0.00015,0.00009,0.00018,0.00015,0.00015,0.00015,0.00017,0.00018,0.00018,0.00015,0.00018,0.00020,0.00024,0.00021,0.00023,0.00027,0.00024,0.00024,0.00027,0.00023,0.00020,0.00029,0.00020,0.00027,0.00020,0.00027,0.00026,0.00034,0.00024,0.00034,0.00031,0.00037,0.00043,0.00038,0.00038,0.00035,0.00047,0.00056,0.00058,0.00041,0.00047,0.00056,0.00072,0.00044,0.00060,0.00072,0.00061,0.00072,0.00066,0.00085,0.00075,0.00078,0.00082,0.00073,0.00108,0.00089,0.00105,0.00105,0.00151,0.00150,0.00110,0.00145,0.00163,0.00160,0.00165,0.00232,0.00201,0.00371,0.00365,0.00383,0.00459,0.00583,0.00662,0.00984,0.00969,0.01080,0.01379,0.02063,0.04308,0.05960,0.15816,0.59464
 set histogram_type=default;
 set histogram_size=default;
 use test;

mysql-test/t/statistics.test

@@ -576,8 +576,8 @@ ANALYZE TABLE City;
 FLUSH TABLES;
 --enable_result_log
 
---query_vertical select UPPER(db_name),UPPER(table_name),UPPER(column_name),min_value,max_value,nulls_ratio,avg_length,avg_frequency,hist_size,hist_type,hex(histogram),decode_histogram(histogram,hist_type) from mysql.column_stats where UPPER(db_name)='WORLD' and UPPER(table_name)='COUNTRYLANGUAGE' and UPPER(column_name) = 'PERCENTAGE';
---query_vertical select UPPER(db_name),UPPER(table_name),UPPER(column_name),min_value,max_value,nulls_ratio,avg_length,avg_frequency,hist_size,hist_type,hex(histogram),decode_histogram(histogram,hist_type) from mysql.column_stats where UPPER(db_name)='WORLD' and UPPER(table_name)='CITY' and UPPER(column_name) = 'POPULATION';
+--query_vertical select UPPER(db_name),UPPER(table_name),UPPER(column_name),min_value,max_value,nulls_ratio,avg_length,avg_frequency,hist_size,hist_type,hex(histogram),decode_histogram(hist_type,histogram) from mysql.column_stats where UPPER(db_name)='WORLD' and UPPER(table_name)='COUNTRYLANGUAGE' and UPPER(column_name) = 'PERCENTAGE';
+--query_vertical select UPPER(db_name),UPPER(table_name),UPPER(column_name),min_value,max_value,nulls_ratio,avg_length,avg_frequency,hist_size,hist_type,hex(histogram),decode_histogram(hist_type,histogram) from mysql.column_stats where UPPER(db_name)='WORLD' and UPPER(table_name)='CITY' and UPPER(column_name) = 'POPULATION';
 
 set histogram_type=default;
 set histogram_size=default;

sql/item_strfunc.cc

@@ -567,7 +567,7 @@ String *Item_func_decode_histogram::val_str(String *str)
   int type;
 
   tmp.length(0);
-  if (!(res= args[1]->val_str(&tmp)) ||
+  if (!(res= args[0]->val_str(&tmp)) ||
       (type= find_type(res->c_ptr_safe(),
                        &hystorgam_types_typelib, MYF(0))) <= 0)
   {
@@ -577,7 +577,7 @@ String *Item_func_decode_histogram::val_str(String *str)
   type--;
 
   tmp.length(0);
-  if (!(res= args[0]->val_str(&tmp)))
+  if (!(res= args[1]->val_str(&tmp)))
   {
     null_value= 1;
     return 0;