Sql的一些收集
Mysql交集:
mysql不提供intersect求交集。
提供intersect的命令如下:
兩個表的交集:(SELECT ColumnB FROM TableA WHERE ColumnA='Value1')
三個表的交集:
Mysql命令如下:
兩個表的交集:
SELECT * FROM TableA AS TA, TableB AS TB WHERE TA.ColumnA='Value1' AND TB.ColumnA='Value2'
三個表的交集
SELECT * FROM TableA AS TA, TableB AS TB,TableC AS TC WHERE TA.ColumnA='Value1' AND TB.ColumnA='Value2'
mysql不提供intersect求交集。
提供intersect的命令如下:
兩個表的交集:(SELECT ColumnB FROM TableA WHERE ColumnA='Value1')
INTERSECT (SELECT ColumnB FROM TableB WHERE ColumnA='Value2')
三個表的交集:
(SELECT ColumnB FROM TableA WHERE ColumnA='Value1')INTERSECT (SELECT ColumnB FROM TableB WHERE ColumnA='Value2')INTERSECT (SELECT ColumnB FROM TableC WHERE ColumnA='Value3')
Mysql命令如下:
兩個表的交集:
SELECT * FROM TableA AS TA, TableB AS TB WHERE TA.ColumnA='Value1' AND TB.ColumnA='Value2'
AND TA.ColumnB=TB.ColumnB
三個表的交集
SELECT * FROM TableA AS TA, TableB AS TB,TableC AS TC WHERE TA.ColumnA='Value1' AND TB.ColumnA='Value2'
AND TA.ColumnB=TB.ColumnB and TA.ColumnA=TC.CloumnB;
Mysql的清除表內(nèi)容: truncate table
Mysql 查詢數(shù)據(jù)導(dǎo)出到文件 select * from tableA into outfile 'c:\a.txt';
Mysql 復(fù)制表結(jié)構(gòu) select * into table_new from tableA;
posted on 2010-01-12 12:03 草原上的駱駝 閱讀(298) 評論(0) 編輯 收藏 所屬分類: 數(shù)據(jù)庫-DataBase