sybase数据类型层次

类似于java中的基本数据类型转换

select name, hierarchy from systypes order by hierarchy;

列出类型层次关系:
name                           hierarchy  
----                           -----------
floatn                                   1
float                                    2
datetimn                                 3
datetime                                 4
real                                     5
numericn                                 6
numeric                                  7
decimaln                                 8
decimal                                  9
moneyn                                  10
money                                   11
smallmoney                              12
smalldatetime                           13
intn                                    14
int                                     15
smallint                                16
tinyint                                 17
bit                                     18
univarchar                              19
unichar                                 20
sysname                                 22
varchar                                 22
nvarchar                                22
char                                    23
nchar                                   23
timestamp                               24
varbinary                               24
binary                                  25
text                                    26
image                                   27
date                                    28
time                                    29
daten                                   30
timen                                   31
extended type                           99

例如:smallint(c1)*int(c2)最后结果为int型,因为int的hierarchy值为15,而smallint为16.