This post aims to give readers a primer on SQL-flavored merging with Pandas, how to use it, and when not to use it. In particular, here’s what this post will go through: The basics – types of joins (LEFT, RIGHT, OUTER, INNER) merging with different column names merging with multiple columns avoiding duplicate merge key … Read more
Reading this original article on The Code Project will help you a lot: Visual Representation of SQL Joins. Also check this post: SQL SERVER – Better Performance – LEFT JOIN or NOT IN?. Find original one at: Difference between JOIN and OUTER JOIN in MySQL.
Assuming you’re joining on columns with no duplicates, which is a very common case: An inner join of A and B gives the result of A intersect B, i.e. the inner part of a Venn diagram intersection. An outer join of A and B gives the results of A union B, i.e. the outer parts … Read more
Use LEFT JOIN: SELECT VA.COL_PERSONNEL_NUMBER, VA.COL_CLOCK_DATE, VA.P10, VA.P20, VR.NAME, VR.UNIT FROM VIEW_ABSEN VA LEFT JOIN VIEW_REPORT VR ON VA.COL_PERSONNEL_NUMBER=VR.ID AND VR.DATE=VA.COL_CLOCK_DATE WHERE VA.COL_PERSONNEL_NUMBER LIKE ‘%521663%’ AND VA.COL_CLOCK_DATE BETWEEN ‘2016-08-01’ AND ‘2016-08-05’
You can do this either by a JOIN or Sub-query Sub-query documentation JOIN documentation
Because you screwed syntax order… Multi join works like this: select u.user_name,u.user_emailid,u.user_mobno, q.que1_name,q.qa1,q.que2_name,q.qa2,q.que3_name,q.qa3,q.que4_name,q.qa4,q.que5_name,q.qa5,q. que6a_name,q.qa6a,q.que6b_name,q.qa6b,q.que7_name,q.qa7, r1.ref_name,r1.ref_email,r1.ref_mobno, q.que1_name,q.qa1,q.que2_name,q.qa2,q.que3_name,q.qa3,q.que4_name,q.qa4,q.que5_name,q.qa5,q. que6a_name,q.qa6a,q.que6b_name,q.qa6b,q.que7_name,q.qa7, r2.ref_name,r2.ref_email,r2.ref_mobno, q.que1_name,q.qa1,q.que2_name,q.qa2,q.que3_name,q.qa3,q.que4_name,q.qa4,q.que5_name,q.qa5,q. que6a_name,q.qa6a,q.que6b_name,q.qa6b,q.que7_name,q.qa7, r3.ref_name,r3.ref_email,r3.ref_mobno, q.que1_name,q.qa1,q.que2_name,q.qa2,q.que3_name,q.qa3,q.que4_name,q.qa4,q.que5_name,q.qa5,q. que6a_name,q.qa6a,q.que6b_name,q.qa6b,q.que7_name,q.qa7 from question q LEFT JOIN user u USING(user_id) LEFT JOIN reference_1 r1 USING(ref_id_1) LEFT JOIN reference_2 r2 USING(ref_id_2) LEFT JOIN reference_3 r3 USING(ref_id_3) WHERE q.flag = 1 Where must be at the … Read more
You can use GROUP BY keyword for grouping them, your query will become something like this SELECT pm.receiptID , pm.recievedAmount , pd.invono , pd.paidAmount FROM PaymentMaster pm LEFT JOIN PaymentDetail pd ON pd.receiptID = pm.receiptID GROUP BY pd.receiptID
Answers (b) and (d) are totally wrong. The query won’t return any rows from TableA. If there are any matching rows are found in TableA, those rows get excluded by the condition in the WHERE clause. (Note that any value of columnName that satisfies the equality comparison in the ON clause will be non-NULL, and … Read more