SELECT table1.id, table2.x, table3.x FROM (table1 LEFT JOIN table2 ON table1.id=table2.id) LEFT JOIN table3 ON table1.id=table3.id我用了上面的语句,发现执行的结果的记录数比table1的记录数多, 如果才能做到和table1的记录数一样多呢,
SELECT table1.id, table2.x, table3.x from table1 left join table2 on table1.id=table2.id left join table3 on table1.id=table3.id加()干什么???
SELECT chx.jsyname, chx.chh, chx1.zyj, chx2.zyj FROM chx LEFT JOIN chx1 ON chx.jsyname=chx1.jsyname LEFT JOIN chx2 ON chx.jsyname=chx2.jsyname;就是上面的语句啊,大家帮我看看啊
SELECT distinct chx.jsyname, chx.chh, chx1.zyj, chx2.zyj FROM chx LEFT JOIN chx1 ON chx.jsyname=chx1.jsyname LEFT JOIN chx2 ON chx.jsyname=chx2.jsyname;
SELECT table1.id, table2.x, table3.x FROM (table1 LEFT JOIN table2 ON table1.id=table2.id) LEFT JOIN table3 ON table1.id=table3.id
还有,重复的语句我不要显示
SELECT table1.id, table2.x, table3.x
FROM (table1 LEFT JOIN table2 ON table1.id=table2.id) LEFT JOIN table3 ON table1.id=table3.id我用了上面的语句,发现执行的结果的记录数比table1的记录数多,
如果才能做到和table1的记录数一样多呢,
from table1 left join table2 on table1.id=table2.id
left join table3 on table1.id=table3.id加()干什么???
FROM chx LEFT JOIN chx1 ON chx.jsyname=chx1.jsyname LEFT JOIN chx2 ON chx.jsyname=chx2.jsyname;就是上面的语句啊,大家帮我看看啊
FROM chx LEFT JOIN chx1 ON chx.jsyname=chx1.jsyname LEFT JOIN chx2 ON chx.jsyname=chx2.jsyname;
FROM (table1 LEFT JOIN table2 ON table1.id=table2.id) LEFT JOIN table3 ON table1.id=table3.id