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## Find ALL duplicate recods by value (without grouping them by value) ##
# to find the duplicate,
# replace all instances of tableName with your table name
# and all instances of duplicateField with the field name where you look for duplicates
SELECT t1.*
FROM tableName AS t1
INNER JOIN(
SELECT duplicateField
FROM tableName
GROUP BY duplicateField
HAVING COUNT(duplicateField) > 1
)temp ON t1.duplicateField = temp.duplicateField
order by duplicateField
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SELECT varchar_col
FROM table
GROUP BY varchar_col
HAVING COUNT(*) > 1;
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SELECT col, COUNT(col) FROM table_name GROUP BY col HAVING COUNT(col) > 1;
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SELECT
col,
COUNT(col)
FROM
table_name
GROUP BY col
HAVING COUNT(col) > 1;
Code language: SQL (Structured Query Language) (sql)
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SELECT
col1, COUNT(col1),
col2, COUNT(col2)
FROM
table_name
GROUP BY
col1,
col2
HAVING
(COUNT(col1) > 1) AND
(COUNT(col2) > 1);
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-- multiple columns
SELECT COUNT(*) c ,
CONCAT(students.first_name, "----",students.last_name)
FROM students WHERE students.class_id = classes.id
GROUP BY CONCAT(first_name,"----",last_name) HAVING c > 1;
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SELECT
col,
COUNT(col)
FROM
table_name
GROUP BY col
HAVING COUNT(col) > 1;
Code language: SQL (Structured Query Language) (sql)
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-- You can duplicate or "clone" a table's contents by executing
> CREATE TABLE new_table AS SELECT * FROM original_table;
-- keep in mind that new new_table inherits ONLY the basic column definitions, null settings
-- and default values of the original_table. It does not inherit indexes and auto_increment
-- definitions.
-------------------------------------------------------------------------------------------
-- To inherit all table definitions
> CREATE TABLE new_table LIKE original_table; -- copy table structure only
> INSERT INTO new_table SELECT * FROM original_table; -- add data from old table