9.5. 秈﹃ㄧ计㎝巨才

セ竊磞瓃êㄇ浪琩㎝巨摸 bytea 计ㄧ计㎝巨才

SQL ﹚竡ㄇΤ疭粂猭﹃ㄧ计 硂ㄇㄧ计柑ㄏノ疭闽龄τぃ琌硆腹ㄓだ筳把计 冈薄叫ǎ Table 9-9 ㄇㄧ计龟瞷ㄏノ盽ノ粂猭秈︽ㄧ计秸ノよ猭 (把綷 Table 9-10)

Table 9-9. SQL 秈﹃ㄧ计㎝巨才

ㄧ计摸磞瓃ㄒ挡狦
string || string bytea ﹃硈钡 '\\\\Post'::bytea || '\\047gres\\000'::bytea\\Post'gres\000
octet_length(string)integer秈﹃い竊计ヘoctet_length('jo\\000se'::bytea)5
position(substring in string)integer﹚﹃竚position('\\000om'::bytea in 'Th\\000omas'::bytea)3
substring(string [from integer] [for integer])bytea ┾﹃ substring('Th\\000omas'::bytea from 2 for 3)h\000o
trim([both] bytes from string) byteastring 秨繷㎝挡Ю埃  bytes 程﹃ trim('\\000'::bytea from '\\000Tom\\000'::bytea)Tom
get_byte(string, offset)integer 眖﹃い┾竊 get_byte('Th\\000omas'::bytea, 4)109
set_byte(string, offset, newvalue)bytea 砞竚﹃い竊 set_byte('Th\\000omas'::bytea, 4, 64)Th\000o@as
get_bit(string, offset)integer 眖﹃い┾ get_bit('Th\\000omas'::bytea, 45)1
set_bit(string, offset, newvalue)bytea 砞竚﹃い set_bit('Th\\000omas'::bytea, 45, 0)Th\000omAs

临Τㄇ秈﹃矪瞶ㄧ计ㄏノTable 9-10 ㄤいΤㄇ琌ず场ㄏノノ龟瞷Table 9-9 SQL 夹非﹃ㄧ计

Table 9-10. ㄤウ秈﹃ㄧ计

ㄧ计摸磞瓃ㄒ挡狦
btrim(string bytea, bytes bytea)byteastring 秨繷㎝挡Ю埃(篒耞)  bytes 柑竊程﹃ btrim('\\000trim\\000'::bytea,'\\000'::bytea)trim
length(string)integer 秈﹃ length('jo\\000se'::bytea)5
decode(string text, type text) bytea р玡ノencode()絪絏 string 柑 秈﹃秆絏把计摸㎝encode()柑妓 decode('123\\000456', 'escape')123\000456
encode(string bytea, type text) text р秈﹃絪絏 ASCII 瞷Α 摸琌 base64hexescapeencode('123\\000456'::bytea, 'escape')123\000456